XMC4400 Errata Sheet for Steps EES-AA, ES-AA

XMC4400 Errata Sheet for Steps EES-AA, ES-AA
Errata Sheet
Rel. 1.3, 2014-04
Device
XMC4400
Marking/Step
EES-AA, ES-AA
Package
PG-LQFP-64/100
Overview
Document ID is 02512AERRA.
This “Errata Sheet” describes product deviations with respect to the user
documentation listed below.
Table 1
Current User Documentation
Document
Version Date
XMC4400 Reference Manual
V1.5
April 2014
XMC4400 Data Sheet
V1.1
March 2014
Make sure that you always use the latest documentation for this device listed in
category “Documents” at http://www.infineon.com/xmc4000.
Notes
1. The errata described in this sheet apply to all temperature and frequency
versions and to all memory size and configuration variants of affected
devices, unless explicitly noted otherwise.
2. Devices marked with EES or ES are engineering samples which may not be
completely tested in all functional and electrical characteristics, therefore
they must be used for evaluation only. Specific test conditions for EES and
ES are documented in a separate “Status Sheet”, delivered with the device.
3. XMC4000 devices are equipped with an ARM® Cortex™-M4 core. Some of
the errata have a workaround which may be supported by some compiler
tools. In order to make use of the workaround the corresponding compiler
switches may need to be set.
XMC4400, EES-AA, ES-AA
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Errata Sheet
Conventions used in this Document
Each erratum is identified by Module_Marker.TypeNumber:
•
•
•
•
Module: Subsystem, peripheral, or function affected by the erratum.
Marker: Used only by Infineon internal.
Type: type of deviation
– (none): Functional Deviation
– P: Parametric Deviation
– H: Application Hint
– D: Documentation Update
Number: Ascending sequential number. As this sequence is used over
several derivatives, including already solved deviations, gaps inside this
enumeration can occur.
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Errata Sheet
History List / Change Summary
1
History List / Change Summary
Table 2
History List
Version
Date
Remark
1.0
2013-02
Initial Version
1.1
2013-05
Added: PORTS_CM.005, STARTUP_CM.001
1.2
2013-09
Added: ADC_AI.008, CCU8_AI.002,
CCU8_AI.004, CPU_CM.004, HRPWM_AI.003.
Updated: RESET_CM.H001
1.3
2014-04
This Document. For changes see column "Chg"
in the tables below.
Table 3
Errata fixed in this step
Errata
Short Description
Change
- none Table 4
Functional Deviations
Functional
Deviation
Short Description
ADC_AI.002
Result of Injected Conversion may be
wrong
7
ADC_AI.008
Wait-for-Read condition for register
GLOBRES not detected in continuous
auto-scan sequence
7
ADC_TC.064
Effect of conversions in 10-bit fast
compare mode on post-calibration
CCU8_AI.002
CC82 Timer of the CCU8x module cannot
use the external shadow transfer trigger
connected to the POSIFx module
9
CCU8_AI.003
CCU8 Parity Checker Interrupt Status is
cleared automatically by hardware
11
XMC4400, EES-AA, ES-AA
3/55
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Chg Pg
New 8
Rel. 1.3, 2014-04
Errata Sheet
History List / Change Summary
Table 4
Functional Deviations (cont’d)
Functional
Deviation
Short Description
CCU8_AI.004
CCU8 output PWM glitch when using low
side modulation via the Multi Channel
Mode
14
CCU_AI.002
CCU4 and CCU8 Prescaler
synchronization clear does not work when
Module Clock is faster than Peripheral Bus
Clock
17
CCU_AI.004
CCU4 and CCU8 Extended Read Back loss
of data
18
CCU_AI.005
CCU4 and CCU8 External IP clock Usage
19
CPU_CM.001
Interrupted loads to SP can cause
erroneous behavior
21
CPU_CM.004
VDIV or VSQRT instructions might not
complete correctly when very short ISRs
are used
23
DSD_AI.001
Possible Result Overflow with Certain
Decimation Factors
ETH_AI.001
Incorrect IP Payload Checksum at
incorrect location for IPv6 packets with
Authentication extension header
25
ETH_AI.002
Incorrect IP Payload Checksum Error
status when IPv6 packet with
Authentication extension header is
received
26
ETH_AI.003
Overflow Status bits of Missed Frame and
Buffer Overflow counters get cleared
without a Read operation
27
ETH_CM.001
Ethernet module synchronization limits
CPU frequency
28
XMC4400, EES-AA, ES-AA
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Chg Pg
New 24
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Errata Sheet
History List / Change Summary
Table 4
Functional Deviations (cont’d)
Functional
Deviation
Short Description
Chg Pg
HRPWM_AI.001
HRPWM output signal interference while
using two control sources
28
HRPWM_AI.003
HRPWM Usage Limitations
30
HRPWM_AI.004
HRPWM Peripheral Bus Clock Limitation
LEDTS_AI.001
Delay in the update of FNCTL.PADT bit
field
34
PMU_CM.001
Branch from non-cacheable to cacheable
address space instruction may corrupt the
program execution
38
PORTS_CM.002
P0.9 Pull-up permanently active
40
PORTS_CM.005
Different PORT register reset values after
module reset
41
POSIF_AI.001
Input Index signal from Rotary Encoder is
not decoded when the length is 1/4 of the
tick period
42
SCU_CM.006
Deep sleep entry with PLL power-down
option generates SOSCWDGT and
SVCOLCKT trap
44
SCU_CM.015
Parity Memory Test function not usable
New 45
New 33
STARTUP_CM.00 CAN Bootstrap Loader
1
45
USIC_AI.008
SSC delay compensation feature cannot
be used
New 45
USIC_AI.010
Minimum and maximum supported word
and frame length in multi-IO SSC modes
46
USIC_AI.013
SCTR register bit fields DSM and HPCDIR
are not shadowed with start of data word
transfer
46
USIC_AI.014
No serial transfer possible while running
capture mode timer
47
XMC4400, EES-AA, ES-AA
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History List / Change Summary
Table 4
Functional Deviations (cont’d)
Functional
Deviation
Short Description
USIC_AI.015
Wrong generation of FIFO standard
transmit/receive buffer events when
TBCTR.STBTEN/RBCTR.SRBTEN = 1
47
USIC_AI.016
Transmit parameters are updated during
FIFO buffer bypass
47
USIC_AI.017
Clock phase of data shift in SSC slave
cannot be changed
48
USIC_AI.018
Clearing PSR.MSLS bit immediately
deasserts the SELOx output signal
48
USIC_AI.019
First data word received by IIC receiver
triggers RIF instead of AIF
49
USIC_AI.020
Handling unused DOUT lines in multi-IO
SSC mode
Table 5
Chg Pg
New 50
Application Hints
Hint
Short Description
ADC_AI.H004
Completion of Startup Calibration
ADC_TC.H011
Bit DCMSB in register GLOBCFG
MultiCAN_AI.H005
TxD Pulse upon short disable request
51
MultiCAN_AI.H006
Time stamp influenced by
resynchronization
52
MultiCAN_AI.H007
Alert Interrupt Behavior in case of BusOff
52
MultiCAN_AI.H008
Effect of CANDIS on SUSACK
53
MultiCAN_TC.H003
Message may be discarded before
transmission in STT mode
53
MultiCAN_TC.H004
Double remote request
53
RESET_CM.H001
Power-On Reset Release
54
XMC4400, EES-AA, ES-AA
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Chg Pg
51
New 51
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Errata Sheet
Functional Deviations
2
Functional Deviations
The errata in this section describe deviations from the documented functional
behavior.
ADC_AI.002 Result of Injected Conversion may be wrong
In cancel-inject-repeat mode (GxARBPR.CSM* = 1B), the result of the higher
prioritized injected conversion cH may be wrong if it was requested within a
certain time window at the end of a lower prioritized conversion cL. The width of
the critical window depends on the divider factor DIVA for the analog internal
clock.
Workaround
Do not use cancel-inject-repeat mode. Instead, use wait-for-start mode
(GxARBPR.CSM* = 0B).
ADC_AI.008 Wait-for-Read condition for register GLOBRES not detected
in continuous auto-scan sequence
In the following scenario:
•
•
A continuous auto-scan is performed over several ADC groups and
channels by the Background Scan Source, using the global result register
(GLOBRES) as result target (GxCHCTRy.RESTBS=1B), and
The Wait-for-Read mode for GLOBRES is enabled (GLOBRCR.WFR=1B),
each conversion of the auto-scan sequence has to wait for its start until the
result of the previous conversion has been read out of GLOBRES.
When the last channel of the auto-scan is converted and its result written to
GLOBRES, the auto-scan re-starts with the highest channel number of the
highest ADC group number. But the start of this channel does not wait until the
result of the lowest channel of the previous sequence has been read from
register GLOBRES, i.e. the result of the lowest channel may be lost.
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Functional Deviations
Workaround
If either the last or the first channel in the auto-scan sequence does not write its
result into GLOBRES, but instead into its group result register (selected via bit
GxCHCTRy.RESTBS=0B), then the Wait-for-Read feature for GLOBRES works
correctly for all other channels of the auto-scan sequence.
For this purpose, the auto-scan sequence may be extended by a “dummy”
conversion of group x/ channel y, where the Wait-for-Read mode must not be
selected (GxRCRy.WFR=0B) if the result of this “dummy” conversion is not
read.
ADC_TC.064 Effect of conversions in 10-bit fast compare mode on postcalibration
The calibrated converters Gx (x = 0..3) support post-calibration. Unless
disabled by software (via bits GLOBCFG.DPCALx = 0), a calibration step is
performed after each conversion, incrementally increasing/decreasing internal
calibration values to compensate process, temperature, and voltage variations.
If a conversion in 10-bit fast-compare mode (bit field CMS/E = 101B in
corresponding Input Class register) is performed between two conversions in
other (non-fast-compare) modes on a converter Gx, the information gained from
the last post-calibration step is disturbed. This will lead to a slightly less
accurate result of the next conversion in a non-fast-compare mode.
Depending on the ratio of conversions in fast-compare mode versus
conversions in other modes, this effect will be more or less obvious.
In a worst case scenario (fast-compare with a constant result injected between
each two normal conversions), all calibration values can drift to their maxima /
minima, causing the converter Gx to deliver considerably inaccurate results.
Workaround
Do not perform conversions using 10-bit fast-compare mode on the calibrated
converters Gx (x = 0..3). Instead, use the uncalibrated converters Gy (y = 4..7)
to perform conversions in fast-compare mode.
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Functional Deviations
CCU8_AI.002 CC82 Timer of the CCU8x module cannot use the external
shadow transfer trigger connected to the POSIFx module
Each CCU8 Module Slice contains 4 identical timers (CC80, CC81, CC82 and
CC83). There is the possiblity of updating the values controlling the duty cycle,
period, output passive level, dither and floating prescaler on-the-fly of each and
every timer, with a SW request. The update request of these values can also be
done via an external trigger that is connected to the POSIFx module Figure 1.
An update action of any of these values is named as “shadow transfer”.
The signal between the POSIFx and CCU8x module is used to handshake a
concurrent update between several registers, contained in the two modules.
The output signal of the POSIFx is named as POSIFx.OUT6 while the input
signal on the CCU8x side is named as CCU8x.MCSS.
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Functional Deviations
CCU8x (CCU8 Module x)
CC83 (Timer3)
CC82 (Timer2)
CC81 (Timer1)
CC80 (Timer0)
SW writes 1b to this field to
request an update of the values
controlling the period, duty and
output passive level
POSIFx (Position Interface Module x)
GCSS.SySE
Multi Channel Feature
GCTRL.MSEy
≥1
SW writes 1b to this field to
request an update of the values
controlling the dither
GCSS.SyDSE
≥1
GCTRL.MSDE
SW writes 1b to this field to
request an update of the values
controlling the floating prescaler
GCSS.SyDSE
≥1
GCTRL.MSDE
Figure 1
Value update trigger connection between CCU8x and POSIFx
On Figure 2, we see an example how this trigger is used to update at the same
time teh duty cycle value of a timer inside the CCU8x and the multi channel
pattern inside the POSIFx (the multi channel pattern can affect the CCU8x timer
outputs therefore a synchronous update of all the values solves possible output
glitches on the generated PWM signals).
On Figure 2, the SW has updated the next values for the duty cycle on a CCU8x
Timer (it can be also for the period, output passive level and clock prescaler).
After that it updates also the next value of the multi channel pattern inside the
POSIFx module. After that, the POSIF reaches an internal state (dictated by
specific conditions) where an update of the values is needed. it generates a
trigger signal to the CCU8x Timer to signalize that an update of the duty cycle
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Functional Deviations
value needs to be done. After that timeframe, the POSIF waits for the
handshake trigger of the CCU8x Timer to indicate that an update is going to be
performed. At this specific time, both the values of the CCU8x Timer and POSIF
are update completely synchronous.
This feature cannot be used with the Timer2 (defined as CC82 in the
documentation) of the CCU8x module(s) (more than one CCU8 module can be
contained on a specific device).
All the other 3 Timers (defined as CC80, CC81, CC83) inside the CCU8x
moduel are not affected by this issue.
CCU8x
Timer
Current duty
cycle value
Next duty
cycle value
Valuen
CCU8x
Valuen+1
Valuen
Valuen+1
Update is
requested
Update trigger
POSIFx shadow
transfer trigger
Current multi
channel pattern
Figure 2
Valuen+1
Valuen
Next multi
channel pattern
Valuen
POSIFx
Valuen+1
Value update handshake between CCU8x and POSIFx
Workaround
None
CCU8_AI.003 CCU8 Parity Checker Interrupt Status is cleared automatically by hardware
Each CCU8 Module Timer has an associated interrupt status register. This
Status register, CC8yINTS, keeps the information about which interrupt source
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Functional Deviations
triggered an interrupt. The status of this interrupt source can only be cleared by
software. This is an advantage because the user can configure multiple
interrupt sources to the same interrupt line and in each triggered interrupt
routine, it reads back the status register to know which was the origin of the
interrupt.
Each CCU8 module also contains a function called Parity Checker. This Parity
Checker function, crosschecks the output of a XOR structure versus an input
signal, as seen in Figure 1.
When using the parity checker function, the associated status bitfield, is cleared
automatically by hardware in the next PWM cycle whenever an error is not
present.
This means that if in the previous PWM cycle an error was detected and one
interrupt was triggered, the software needs to read back the status register
before the end of the immediately next PWM cycle.
This is indeed only necessary if multiple interrupt sources are ORed together in
the same interrupt line. If this is not the case and the parity checker error source
is the only one associated with an interrupt line, then there is no need to read
back the status information. This is due to the fact, that only one action can be
triggered in the software routine, the one linked with the parity checker error.
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Functional Deviations
Selection
GPCHK.PCTS
CCU8x.OUT00
XOR
CCU8x.OUT01
CC80
XOR
CCU8x.OUT02
XOR
CCU8x.OUT03
XOR
CCU8x.OUT10
XOR
CCU8x.OUT11
CC81
XOR
CCU8x.OUT12
XOR
CCU8x.OUT13
XOR
CCU8x.OUT20
XOR
CCU8x.OUT21
CC82
XOR
CCU8x.OUT22
XOR
CCU8x.OUT23
XOR
CCU8x.OUT30
XOR
CCU8x.OUT31
CC83
XOR
CCU8x.OUT32
XOR
CCU8x.OUT33
XOR
Input Signal
Error detection
Logic
Set
Interrupt
Status
Interrupt
GPCHK.PISEL
Figure 3
Parity Checker diagram
Workaround
Not ORing the Parity Checker error interrupt with any other interrupt source.
With this approach, the software does not need to read back the status
information to understand what was the origin of the interrupt - because there
is only one source.
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Functional Deviations
CCU8_AI.004 CCU8 output PWM glitch when using low side modulation
via the Multi Channel Mode
Each CCU8 Timer Slice can be configured to use the Multi Channel Mode - this
is done by setting the CC8yTC.MCME1 and/or CC8yTC.MCME2 bit fields to 1B.
Each bit field enables the multi channel mode for the associated compare
channel of the CCU8 Timer Slice (each CCU8 Timer Slice has two compare
channels that are able to generate each a complementary pair of PWM
outputs).
After enabled, the Multi Channel mode is then controlled by several input
signals, one signal per output. Whenever an input is active, the specific PWM
output is set to passive level - Figure 1.
The Multi Channel mode is normally used to modulate in parallel several PWM
outputs (a complete CCU8 - up to 16 PWM signals can be modulated in
parallel).
A normal use case is the parallel control of the PWM output for BLDC motor
control. In Figure 2, we can see the Multi Channel Pattern being updated
synchronously to the PWM signals. Whenever a multi channel input is active (in
this case 0), the specific output is set into passive level (the level in which the
external switch is OFF).
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Functional Deviations
CC8y – Timer Slice y
(output view only)
Compare Channel 1 Path
CCU8x.MCIy[0]
0
CC8yTC.MCME1
CCU8x.MCIy[1]
Multi Channel
mode inputs
for a specific
Timer Slice
CCU8x.OUTy0
Other
sources
1
1
A
N
D
0
CCU8x.OUTy1
Compare Channel 2 Path
CCU8x.MCIy[2]
A
N
D
1
1
0
CC8yTC.MCME2
CCU8x.MCIy[3]
CCU8x.OUTy2
The specific
outputs is set
to passive
whenever
associated
multi channel
input is active
Other
sources
1
1
Figure 4
A
N
D
1
1
0
A
N
D
CCU8x.OUTy3
Multi Channel Mode diagram
CCU8x.OUT00
CCU8x.OUT01
CCU8x.OUT02
CCU8x.OUT03
CCU8x.OUT10
CCU8x.OUT11
Multi channel pattern
Figure 5
011101 b
110101 b
110101b
Multi Channel Mode applied to several CCU8 outputs
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Functional Deviations
A glitch is present at the PWM outputs whenever the dead time of the specific
compare channel is enabled - CC8yDTC.DTE1 and/or CC8yDTC.DTE2 set to
1B (each compare channel has a separate dead time function) - and the specific
multi channel pattern for the channel is 01B or 10B.
This glitch is not present if the specific timer slice is configure in symmetric edge
aligned mode - CC8yTC.TCM = 0B and CC8yCHC.ASE = 0B.
This glitch only affects the PWM output that is linked to the inverting ST path of
each compare channel (non inverting outputs are not affected).
The effect of this glitch can be seen in Figure 3. The duration of the PWM glitch
has the same length has the dead time value programmed into the
CC8yDC1R.DT1F field (for compare channel 1) or into the CC8yDC1R.DT2F.
CCU8x.OUT00
CCU8x.OUT01
CCU8x.OUT02
CCU8x.OUT03
CCU8x.OUT10
CCU8x.OUT11
Multi channel pattern
Figure 6
011101 b
110101 b
110101b
PWM output glitch
Workaround
To avoid the glitch on the inverting path of the PWM output, one can disable the
dead time function before the Multi Channel Pattern is set to 01B or 10B.
Disabling the dead time of the inverting PWM output can be done by setting:
CC8yDTC.DCEN2 = 0 //if compare channel 1 is being used
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Functional Deviations
CC8yDTC.DCEN4 = 0 //if compare channel 2 is being used
The dead time needs to be re enabled, before the complementary outputs
become modulated at the same time:
CC8yDTC.DCEN2 = 1 //if compare channel 1 is being used
CC8yDTC.DCEN4 = 1 //if compare channel 2 is being used
CCU_AI.002 CCU4 and CCU8 Prescaler synchronization clear does not
work when Module Clock is faster than Peripheral Bus Clock
Each CCU4/CCU8 module contains a feature that allows to clear the prescaler
division counter synchronized with the clear of a run bit of a Timer Slice. This is
configure via the GCTRL.PRBC field. The default value of 000B dictates that
only the software can clear the prescaler internal division counter. Programming
a value different from 000B into the PRBC will impose that the prescaler division
counter is cleared to 0D whenever the selected Timer Slice (selected via the
PRBC field) run bit is cleared (TRB bit field).
In normal operating conditions, clearing the internal prescaler division counter
is not needed. The only situation were a clear of the division may be needed is
when several Timer Slices inside one unit (CCU4/CCU8) are using different
prescaling factors and a realignment of all the timer clocks is needed. This
normally only has a benefit if there is a big difference between the prescaling
values, e.g. Timer Slice 0 using a module clock divided by 2D and Timer Slice 1
using a module clock divided by 1024D.
When the peripheral bus clock frequency is smaller than the CCU4/CCU8
module clock frequency, fperiph < fccu, it is not possible to clear the prescaler
division counter, synchronized with the clear of the run bit of one specific Timer
Slice.
Workaround 1
The clearing of the prescaler internal division counter needs to be done via
software: GCTRL.PRBC programmed with 000B and whenever a clear is
needed, writing 1B into the GIDLS.CPRB bit field.
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Functional Deviations
Workaround 2
When the usage of the Prescaler internal division clear needs to be
synchronized with a timer run bit clear, the module clock of the CCU4/CCU8
should be equal to the peripheral bus clock frequency: fperiph = fccu.
To do this, the following SCU (System Control Unit) registers should be set with
values that force this condition: CCUCLKCR.CCUDIV, CPUCLKCR.CPUDIV
and PBCLKCR.PBDIV.
CCU_AI.004 CCU4 and CCU8 Extended Read Back loss of data
Each CCU4/CCU8 Timer Slice contains a bit field that allows the enabling of the
Extended Read Back feature. This is done by setting the
CC8yTC.ECM/CC4yTC.ECM = 1B. Setting this bit field to 1B only has an impact
if the specific Timer Slice is working in Capture Mode (CC8yCMC.CAP1S or
CC8yCMC.CAP0S different from 00B - same fields for CCU4).
By setting the bit field to ECM = 1B, is then possible to read back the capture
data of the specific Timer Slice (or multiple Timer Slices, if this bit field is set in
more than one Timer Slice) trough a single address. This address is linked to
the ECRD register.
Referring to Figure 7, the hardware every time that the software reads back
from the ECRD address, will return the immediately next capture register that
contains new data. This is done in a circular access, that contains all the capture
registers from the Timer Slices that are working in capture mode.
When using this feature, there is the possibility of losing captured data within a
Timer Slice. The data that is lost is always the last captured data within a timer
slice, e.g (with CCU4 nomenclature - same applies to CCU8):
•
•
Timer X has 4 capture registers and is the only Timer set with ECM = 1B. At
the moment that the software starts reading the capture registers via the
ECRD address, we have already capture four values. The ECRD read back
will output CC4xC0V -> CC4xC1V -> CC4xC2V -> CC4xC2V (CC4xC3V
value is lost)
Timer X has 4 capture registers and is the only Timer set with ECM = 1B. At
the moment that the software starts reading the capture registers via the
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•
ECRD address, we have already capture two values. The ECRD read back
will output CC4xC2V -> CC4xC2V (CC4xC3V value is lost)
Timer X and Timer Y have 4 capture registers each and they are both
configured with ECM = 1B. At the moment that the software starts reading
the capture registers via the ECRD address, we have already capture two
values on Timer X and 4 on Timer Y. The ECRD read back will output
CC4xC0V -> CC4xC1V -> CC4xC2V -> CC4xC3V -> CC4yC2V ->
CC4yC2V (CC4yC3V value is lost)
Timer Slice 0
CC40C0V
ptr stays if
full
ptr
CC40C1V
ptr stays if
full
ptr
CC41C1V
ptr stays if
full
ptr
CC40C2V
ptr stays if
full
ptr
CC41C2V
ptr stays if
full
ptr
CC42C2V
ptr stays if
full
ptr
CC43C2V
ptr stays if
full
ptr
CC40C3V
ptr stays if
full
ptr
CC41C3V
ptr stays if
full
ptr
CC42C3V
ptr stays if
full
ptr
CC43C3V
ptr stays if
full
ptr
Timer Slice 1
CC41C0V
ptr stays if
full
Timer Slice 2
CC42C0V
ptr stays if
full
ptr
CC42C1V
ptr stays if
full
Timer Slice 3
CC43C0V
ptr stays if
full
ptr
CC43C1V
ptr stays if
full
ptr
SW reads from ECRD address
and HW goes through all capture
registers (in a circular way) and
returns the capture register that
contains new data
ptr
ptr
Figure 7
Extended Read Back access - example for CCU4 (CCU8
structure is the same)
Workaround
None.
CCU_AI.005 CCU4 and CCU8 External IP clock Usage
Each CCU4/CCU8 module offers the possibility of selecting an external signal
to be used as the master clock for every timer inside the module Figure 1.
External signal in this context is understood as a signal connected to other
module/IP or connected to the device ports.
The user has the possibility after selecting what is the clock for the module
(external signal or the clock provided by the system), to also select if this clock
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Functional Deviations
needs to be divided. The division ratios start from 1 (no frequency division) up
to 32768 (where the selected timer uses a frequency of the selected clock
divided by 32768).
This division is selected by the PSIV field inside of the CC4yPSC/CC8yPSC
register. Notice that each Timer Slice (CC4y/CC8y) have a specific PSIV field,
which means that each timer can operate in a different frequency.
Currently is only possible to use an external signal as Timer Clock when a
division ratio of 2 or higher is selected. When no division is selected (divided by
1), the external signal cannot be used.
The user must program the PSIV field of each Timer Slice with a value different
from 0000B - minimum division value is /2.
This is only applicable if the Module Clock provided by the system (the normal
default configuration and use case scenario) is not being used. In the case that
the normal clock configured and programmed at system level is being used,
there is not any type of constraints.
One should not also confuse the usage of an external signal as clock for the
module with the usage of an external signal for counting. These two features
are completely unrelated and there are not any dependencies between both.
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CCU4/CCU8
Module clock
from the system
Module External
Signals
/1
/2
Prescaler
CC40/CC80
...
...
Timer clock
CC4/80PSC.PSIV
/16384
/32768
CC41/CC81
...
Timer clock
CC4/81PSC.PSIV
CC42/CC82
...
Timer clock
CC4/82PSC.PSIV
CC43/CC83
...
Timer clock
CC4/83PSC.PSIV
Figure 8
Clock Selection Diagram for CCU4/CCU8
Workaround
None.
CPU_CM.001 Interrupted loads to SP can cause erroneous behavior
If an interrupt occurs during the data-phase of a single word load to the stackpointer (SP/R13), erroneous behavior can occur. In all cases, returning from the
interrupt will result in the load instruction being executed an additional time. For
all instructions performing an update to the base register, the base register will
be erroneously updated on each execution, resulting in the stack-pointer being
loaded from an incorrect memory location.The affected instructions that can
result in the load transaction being repeated are:
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1.
2.
3.
4.
5.
LDR SP,[Rn],#imm
LDR SP,[Rn,#imm]!
LDR SP,[Rn,#imm]
LDR SP,[Rn]
LDR SP,[Rn,Rm]
The affected instructions that can result in the stack-pointer being loaded from
an incorrect memory address are:
1. LDR SP,[Rn],#imm
2. LDR SP,[Rn,#imm]!
Conditions
1. An LDR is executed, with SP/R13 as the destination
2. The address for the LDR is successfully issued to the memory system
3. An interrupt is taken before the data has been returned and written to the
stack-pointer.
Implications
Unless the load is being performed to Device or Strongly-Ordered memory,
there should be no implications from the repetition of the load. In the unlikely
event that the load is being performed to Device or Strongly-Ordered memory,
the repeated read can result in the final stack-pointer value being different than
had only a single load been performed.
Interruption of the two write-back forms of the instruction can result in both the
base register value and final stack-pointer value being incorrect. This can result
in apparent stack corruption and subsequent unintended modification of
memory.
Workaround
Both issues may be worked around by replacing the direct load to the stackpointer, with an intermediate load to a general-purpose register followed by a
move to the stack-pointer.
If repeated reads are acceptable, then the base-update issue may be worked
around by performing the stack pointer load without the base increment
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followed by a subsequent ADD or SUB instruction to perform the appropriate
update to the base register.
CPU_CM.004 VDIV or VSQRT instructions might not complete correctly
when very short ISRs are used
The VDIV and VSQRT instructions take 14 cycles to execute. When an interrupt
is taken a VDIV or VSQRT instruction is not terminated, and completes its
execution while the interrupt stacking occurs. If lazy context save of floating
point state is enabled then the automatic stacking of the floating point context
does not occur until a floating point instruction is executed inside the interrupt
service routine.
Lazy context save is enabled by default. When it is enabled, the minimum time
for the first instruction in the interrupt service routine to start executing is 12
cycles. In certain timing conditions, and if there is only one or two instructions
inside the interrupt service routine, then the VDIV or VSQRT instruction might
not write its result to the register bank or to the FPSCR.
Conditions
1.
2.
3.
4.
5.
6.
The floating point unit is present and enabled
Lazy context saving is not disabled
A VDIV or VSQRT is executed
The destination register for the VDIV or VSQRT is one of s0 - s15
An interrupt occurs and is taken
The interrupt service routine being executed does not contain a floating
point instruction
7. 14 cycles after the VDIV or VSQRT is executed, an interrupt return is
executed
A minimum of 12 of these 14 cycles are utilized for the context state stacking,
which leaves 2 cycles for instructions inside the interrupt service routine, or 2
wait states applied to the entire stacking sequence (which means that it is not a
constant wait state for every access).In general this means that if the memory
system inserts wait states for stack transactions then this erratum cannot be
observed.
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Implications
The VDIV or VQSRT instruction does not complete correctly and the register
bank and FPSCR are not updated, meaning that these registers hold incorrect,
out of date, data.
Workaround
A workaround is only required if the floating point unit is present and enabled.
A workaround is not required if the memory system inserts one or more wait
states to every stack transaction.
There are two workarounds:
1. Disable lazy context save of floating point state by clearing LSPEN to 0 (bit
30 of the FPCCR at address 0xE000EF34).
2. Ensure that every interrupt service routine contains more than 2 instructions
in addition to the exception return instruction.
DSD_AI.001 Possible Result Overflow with Certain Decimation Factors
Certain combinations of CIC filter grade and oversampling rate (see below) can
lead to an overflow within the CIC filter. These combinations must be avoided
to ensure proper operation of the digital filter.
Critical combinations:
•
•
•
CIC2 (CFMC/CFAC = 01B) with oversampling rate of 182
CIC3 (CFMC/CFAC = 10B) with oversampling rate of 33, 41, 51, 65, 81, 102,
129, 162…182, 204
CICF (CFMC/CFAC = 11B) with oversampling rate of 129, 182
Note: Filter grade and oversampling rate are defined in register
FCFGCx/FCFGAx. The shown oversampling rates are defined as
CFMDF+1/CFADF+1.
Workaround
None.
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ETH_AI.001 Incorrect IP Payload Checksum at incorrect location for IPv6
packets with Authentication extension header
When enabled, the Ethernet MAC computes and inserts the IP header
checksum (IPv4) or TCP, UDP, or ICMP payload checksum in the transmitted
IP datagram (IPv4 or IPv6) on per-packet basis. The Ethernet MAC processes
the IPv6 header and the optional extension headers (if present) to identify the
start of actual TCP, UDP, or ICMP payload for correct computation and
insertion of payload checksum at appropriate location in the packet. The IPv6
header length is fixed (40 bytes) whereas the extension header length is
specified in units of N bytes:
Extension Header Length Field Value x N bytes + 8 bytes
where N = 4 for authentication extension header and N = 8 for all other
extension headers supported by the Ethernet MAC. If the actual payload bytes
are less than the bytes indicated in the Payload Length field of the IP header,
the Ethernet MAC indicates the IP Payload Checksum error.
If the payload checksum is enabled for an IPv6 packet containing the
authentication extension header, then instead of bypassing the payload
checksum insertion, the Ethernet MAC incorrectly processes the packet and
inserts a payload checksum at an incorrect location. As a result, the packet gets
corrupted, and it is dropped at the destination. The software should not enable
the payload checksum insertion for such packets because the Integrity Check
Value (ICV) in the authentication extension header is calculated and inserted
considering that the payload data is immutable (not modified) in transit.
Therefore, even if the payload checksum is correctly calculated and inserted, it
results into a failure of the ICV check at the final destination and the packet is
eventually dropped.
Workaround
The software should not enable the IP payload checksum insertion by the
Ethernet MAC for Tx IPv6 packets with authentication extension headers. The
software can compute and insert the IP payload checksum for such packets.
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ETH_AI.002 Incorrect IP Payload Checksum Error status when IPv6 packet with Authentication extension header is received
The Ethernet MAC processes a TCP, UDP, or ICMP payload in the received IP
datagrams (IPv4 or IPv6) and checks whether the received checksum field
matches the computed value. The result of this operation is given as an IP
Payload Checksum Error in the receive status word. This status bit is also set if
the length of the TCP, UDP, or ICMP payload does not match the expected
payload length given in the IP header.
In IPv6 packets, there can be optional extension headers before actual TCP,
UDP, or ICMP payload. To compute and compare the payload checksum for
such packets, the Ethernet MAC sequentially parses the extension headers,
determines the extension header length, and identifies the start of actual TCP,
UDP, or ICMP payload. The header length of all extension headers supported
by the Ethernet MAC is specified in units of 8 bytes (Extension Header Length
Field Value x 8 bytes + 8 bytes) except in the case of authentication extension
header. For authentication extension header, the header length is specified in
units of 4 bytes (Extension Header Length Field Value x 4 bytes + 8 bytes).
However, because of this defect, the Ethernet MAC incorrectly interprets the
size of the authentication extension header in units of 8 bytes, because of which
the following happens:
•
•
•
•
Incorrect identification of the start of actual TCP, UDP, or ICMP payload
Computing of incorrect payload checksum
Comparison with incorrect payload checksum field in the received IPv6
frame that contains the authentication extension header
Incorrect IP Payload Checksum Error status
As a result, the IP Payload checksum error status is generated for proper IPv6
packets with authentication extension header. If the Ethernet MAC core is
programmed to drop such `error` packets, such packets are not forwarded to
the host software stack.
Workaround
Disable dropping of TCP/IP Checksum Error Frames by setting Bit 26 (DT) in
the Operation Mode Register (OPERATION_MODE). This enables the Ethernet
MAC core to forward all packets with IP checksum error to the software driver.
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The software driver must process all such IPv6 packets that have payload
checksum error status and check whether they contain the authentication
extension header. If authentication extension header is present, the software
driver should either check the payload checksum or inform the upper software
stack to check the packet for payload checksum.
ETH_AI.003 Overflow Status bits of Missed Frame and Buffer Overflow
counters get cleared without a Read operation
The DMA maintains two counters to track the number of frames missed
because of the following:
•
•
Rx Descriptor not being available
Rx FIFO overflow during reception
The Missed Frame and Buffer Overflow Counter register indicates the current
value of the missed frames and FIFO overflow frame counters. This register
also has the Overflow status bits (Bit 16 and Bit 28) which indicate whether the
rollover occurred for respective counter. These bits are set when respective
counter rolls over. These bits should remain high until this register is read.
However, erroneously, when the counter rollover occurs second time after the
status bit is set, the respective status bit is reset to zero.
Effects
The application may incorrectly detect that the rollover did not occur since the
last read operation.
Workaround
The application should read the Missed Frame and Buffer Overflow Counter
register periodically (or after the Overflow or Rollover status bits are set) such
that the counter rollover does not occur twice between read operations.
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ETH_CM.001 Ethernet module synchronization limits CPU frequency
Due to synchronization problems the Ethernet modules DMA data descriptor
pointers may become corrupted. As a consequence the module delivers wrong
data or fails to transfer data at all.
Workaround
Limit the CPU frequency to half of the System frequency (fCPU = .fSYS/2) by
setting bit field CPUDIV of register CPUCLKCR (CPUCLKCR.CPUDIV=1).
HRPWM_AI.001 HRPWM output signal interference while using two control sources
The High Resolution PWM (HRPWM) unit has 4 High Resolution Channel
(HRC) sub modules. These are the sub modules that are used to extend the
normal PWM resolution up to 150 ps. The structure of each of these sub
modules is depicted in Figure 9.
01.02.2013 - 08.02.2013
Switches which group of signals
is associated to the two Paths
N
Inputs
HRCySC.ST
Source Selector 0
EN
High Resolution Path
Set/
Clear
HRCCFG.HRCyE
Enables the path
Dead Time
Output
Control
S
Set/
Clear
N
Inputs
Source Selector 1
R
EN
Q
Q
Output
Output
Low Resolution Path
HRCCFG.LRCyE
Figure 9
SET
CLR
Enables the path
High Resolution Channel (HRC) simplified block diagram
From the scheme of each HRC, it is possible to control the output PWM signal
via two Source Selectors (Source Selector 0 and Source Selector 1). Each of
these Source Selectors can generate a pair of PWM set and clear signals (that
are propagated to the output control stage).
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When both paths are being used (High Resolution Path and Low Resolution
Path), the Source Selector 0 output signals always have priority over the signals
generated via Source Selector 1.
At any given instant a bitfield that controls which Source Selector is connected
to which path can be updated by Software, via the HRCyST.ST bitfield.
When only one path is used (only High Resolution Path or only High Resolution
Path) the software can still update at any given time which is the Source
Selector controlling this specific path (via the HRCyST.ST bitfield).
This scenario where only one path is enabled but both Source Selectors are
being used, and by being used is understood that signals are being actively
decoded from the Source Selectors (input signals for the Source Selectors are
being updated) is depicted on Figure 10 - in this example the High Resolution
Path is the one being used.
01.02.2013 - 08.02.2013
Switches which group of signals
is associated to the two Paths
N
Inputs
N
Inputs
HRCySC.ST
Source Selector 0 set/clear
High
Resolution
Insertion
Dead Time
EN
High Resolution Path
Output
Control
S
R
Source Selector 1
Figure 10
HRCCFG.HRCyE
set/clear
SET
CLR
Q
Q
Output
Output
Enables the path
HRC with only one path enabled and two Source Selectors
In the above scenario, every time that the HRCyST.ST bitfield is 1B, the Source
Selector 1 is the one that has control over the PWM signal. Whenever the
HRCyST.ST bitfield is 0B is the Source Selector 0 that has control over the
PWM signal.
An issue exists whenever the Source Selector 1 is selected (HRCyST.ST = 1B)
and there is a collision between signals from both Source Selectors. A collision
is understood has:
•
at the same module clock time frame Source Selector 0 and Source
Selector 1 both decode a signal (a PWM set or PWM clear).
If the described condition occurs, then the signal generated by Source Selector
1 is lost and the PWM signal is not handled properly - Figure 11.
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HRPWM module
clock
(mclk)
Source Selector 0
SET
Source Selector 0
CLEAR
1 mclk spacing
Source Selector 1
SET
Source Selector 1
CLEAR
PWM
(HRPWM.HROUTyx)
SET from Source
Selector 1 ignored
due to SET on
Source Selector 0
Figure 11
SET from Source
Selector 1 ignored
due to CLEAR on
Source Selector 0
CLEAR from Source
Selector 1 ignored
due to SET on
Source Selector 0
CLEAR from Source
Selector 1 ignored
due to CLEAR on
Source Selector 0
Collision between signals of the two Source Selectors - valid
only when HRCyST.ST = 1B
Workaround 1
Ensuring that the signals controlling both Source Selectors are spaced by a
minimum of 1 HRPWM module clock cycle. This is indeed only necessary if is
currently Source Selector 1 the one selected to control the PWM path
(HRCyST.ST = 1B).
Workaround 2
Ensuring that the signals controlling Source Selector 0 are stopped whenever
Source Selector 1 the one selected to control the PWM path (HRCyST.ST = 1B).
HRPWM_AI.003 HRPWM Usage Limitations
The High Resolution PWM (HRPWM) is comprised of 4 High Resolution
Channels (HRC) and 3 Comparator and Slope Generation sub modules. The
general structure of the peripheral can be seen in Figure 9 (HRPWM = 3xCSGs
+ 4xHRCs).
Each HRC sub module is able to generate a complementary PWM output signal
with a resolution of 150 ps.
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The CSG sub modules contain a high speed comparator and a 10 bit high
speed DAC for reference generation. It is also possible to use the CSG to
generate sawtooth and triangular waveforms via the 10 bit DAC.
Due to power connection issues, in this current device step, the CSG sub
modules are not functional.
Also due to power connection issues, the HRC sub modules can have the
following problems:
•
•
High Resolution Channel 3 may stop working due to internal voltage drop.
Generation of the 150 ps resolution of all the HRCs may not ramp up
properly during module initialization (temperature dependency). If this
happens, then all the HRC channels are not able to generate a 150 ps
resolution.The proper ramp can be check by polling the HRGHRS.HRGR
bitfield.
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High Resolution PWM (HRPWMx)
Comparator & Slope Generation unit 2 (CSG2)
Analog Inputs + Digital Output
Comparator & Slope Generation unit 1 (CSG1)
Comparator & Slope Generation unit 0 (CSG0)
External control
External
+
Filtering
CMP0
External
Blanking
DAC0
Clamping
Slope
Generation 0
Input
Selector
3
8 High Resolution PWMoutputs
High Resolution Channel 3 (HRC3)
High Resolution Channel 2 (HRC2)
High Resolution Channel 1 (HRC1)
From the Timers
High Resolution Channel 0 (HRC0)
{
Mode
qualifier
Time info
S
SET
Q
Output
Control
Dead Time
insertion
Control
Figure 12
High
Resolution
Control
R
CLR
Q
High Resolution Channel (HRC) simplified block diagram
Workaround
None.
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HRPWM_AI.004 HRPWM Peripheral Bus Clock Limitation
The High Resolution PWM (HRPWM) peripheral uses two clocks generated by
the SCU, the module clock (defined as fccu in the System Control Unit) and the
peripheral bus clock (defined as fperiph in the System Control Unit).
The module clock is the one being used by the HRPWM kernel. The peripheral
bus clock is the one being used by the interface between the CPU and the
HRPWM to write and read back the module registers.
Due to synchronization issues, the HRPWM module clock frequency needs to
be the same as the peripheral bus clock frequency (fperiph < fccu).
The peripheral bus clock frequency is controlled via the PBCLKCR.PBDIV field.
The HRPWM module clock frequency is controlled via the
CCUCLKCR.CCUDIV field. Both register are located in the SCU (System
Control Unit).
Workaround
The peripheral bus clock and the module clock of the HRPWM need to have the
same frequency (fperiph = fccu).
This is achieved by setting accordingly the following three fields:
•
•
•
the CCUCLKCR.CCUDIV (field controlling the HRPWM and CCU4, CCU8
and POSIF peripherals module clock ratio);
the CPUCLKCR.CPUDIV (field controlling the CPU clock division ratio);
the PBCLKCR.PBDIV (field controlling the peripheral bus clock division
ratio)
Table 6 shows the valid combinations for each of the previously mentioned
fields. Notice that the frequency values given in the table are just an example
(the real frequency would depend on the specific device and the PLL
configuration).
Table 6
Valid Clock Combinations
Valid CCUCLKCR.CCUDIV CPUCLKCR.CPUDIV PBCLKCR.PBDIV
(frequency example) (frequency example) (frequency example)
Yes
0 (120 MHz)
0 (120 MHz)
0 (120 MHz)
No
0 (120 MHz)
0 (120 MHz)
1 (60 MHz)
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Table 6
Valid Clock Combinations (cont’d)
Valid CCUCLKCR.CCUDIV CPUCLKCR.CPUDIV PBCLKCR.PBDIV
(frequency example) (frequency example) (frequency example)
No
0 (120 MHz)
1 (60 MHz)
0 (60 MHz)
Yes
1 (60 MHz)
0 (120 MHz)
1 (60 MHz)
Yes
1 (60 MHz)
1 (60 MHz)
0 (60 MHz)
LEDTS_AI.001 Delay in the update of FNCTL.PADT bit field
The touch-sense pad turn (PADT) value is updated, not at the end of the touchsense time slice (ColA), but one time slice later (Figure 13).
Time Frame
Active Column
ColA
Current PADT update behavior
Expected PADT update behavior
Figure 13
LED slice
LED slice
Touch‐sense slice
Col1
Col0
ColA
0
0
Col1
Col0
ColA
1
1
Col1
Col0
2
2
3
3
PADT update behavior
If the number of LED columns enabled is smaller than 2, the delay will affect the
activation period of the current active pad. At the beginning of every new Col A,
the value of the current PADT’s compare register is updated to the internal
compare register. However, the delay causes the value of the previous PADT’s
compare register is updated to the internal compare register instead. This
means that the current active pad would be activated with the duration of the
previous pad’s oscillation window (Figure 14). In addition to this, when no LEDs
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are enabled, pad turn 0 will prevail for one time slice longer before it gets
updated (Figure 15).
Time Frame
Active Column
Current PADT update behavior
Internal Compare Register
Figure 14
LED slice
Touch‐sense slice
Col0
ColA
0
Col0
ColA
1
Col0
ColA
2
Col0
ColA
3
Col0
4
CMP_LD0 CMP_TS0 CMP_LD0 CMP_TS1 CMP_LD0 CMP_TS2 CMP_LD0 CMP_TS3 CMP_LD0
Effect of delay on the update of Internal Compare Register
with 1 LED column enabled
Touch‐sense slice = Time frame
Active Column
ColA
Current PADT update behavior
Internal Compare Register
Figure 15
ColA
0
ColA
ColA
ColA
ColA
ColA
ColA
ColA
1
2
3
4
5
6
7
CMP_TS0 CMP_TS1 CMP_TS2 CMP_TS3 CMP_TS4 CMP_TS5 CMP_TS6 CMP_TS7 CMP_TS0
Pad turn 0 prevails for one time slice longer when no LEDs are
enabled
If the number of LED columns enabled is 2 or more, the additional LED columns
would provide some buffer time for the delay. So, at the start of a new touchsense time slice, the update of PADT value would have taken place. Hence, the
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current active PADT compare register value is updated to the internal compare
register (Figure 16).
Time Frame
Active Column
ColA
Current PADT update behavior
Internal Compare Register
Figure 16
LED slice
LED slice
Touch‐sense slice
Col1
Col0
ColA
0
Col1
Col0
1
ColA
2
Col1
Col0
3
CMP_TS0 CMP_LD1 CMP_LD0 CMP_TS1 CMP_LD1 CMP_LD0 CMP_TS2 CMP_LD1 CMP_LD0
Internal Compare Register updated with correct compare
register value with 2 LED columns enabled
Conditions
This delay in PADT update can be seen in cases where hardware pad turn
control mode (FNCTL.PADTSW = 0) is selected and the touch-sense function
is enabled (GLOBCTL.TS_EN = 1).
Workaround
This section is divided to two parts. The first part will provide a guide on reading
the value of the bit field FNCTL.PADT via software. The second part will provide
some workarounds for ensuring that the CMP_TS[x] values are aligned to the
current active pad turn.
Workaround for reading PADT
Due to the delay in the PADT update, the user would get the current active pad
turn when PADT is read in the time frame interrupt. However, this PADT value
read differs when read in a time slice interrupt. This depends on the number of
LED columns enabled and the active function or LED column in the previous
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time slice (Table 7). The bit field FNCTL.FNCOL provides a way of interpreting
the active function or LED column in the previous time slice.
Table 7
PADT value as read in the time slice interrupt
No. of LED
Columns
Enabled
Previous active
function / LED
column
FNCTL.FNCOL
PADT value
0-1
Touch-sense or
LED Col0
110B or 111B
Previous active pad
turn
2-7
Touch-sense or 110B or 111B
first LED column
after touch-sense
Previous active pad
turn
101B to 000B
Second LED
column after
touch-sense
onwards
Current or next
active pad turn
Workaround for aligning CMP_TSx
One workaround is to use the software pad turn control. Then this issue can be
avoided entirely because the pad turn update will have to be handled by
software.
However, it is still possible to work around this issue when using the hardware
pad turn control. In the previous section, it is known that when the number of
LED columns enabled is smaller than 2, the current active pad is activated with
the oscillation window of the previous active pad. This means that the current
active pad is activated with the value programmed in the bit field CMP_TS[x-1]
instead of CMP_TS[x]. There are two possible software workarounds for this
issue:
1. At the end of the time frame interrupt service routine, software can prepare
for the next active pad turn by programming the CMP_TS[x-1] bit field with
the intended compare value for TSIN[x]. As an example, if the next active
pad is TSIN[2], program CMP_TS[1] with the compare value intended for
TSIN[2] (Figure 17).
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Functional Deviations
Time Frame
Active Column
PADT value read
Figure 17
Col0
ColA
0
Col0
ColA
Col0
ColA
Col0
ColA
Col0
1
2
3
4
Time Frame Interrupt
Next active pad = TSIN[2]
Program CMP_TS1 with value intended for TSIN[2]
Time Frame Interrupt
Next active pad = TSIN[3]
Program CMP_TS2 with value intended for TSIN[3]
Time Frame Interrupt
Next active pad = TSIN[4]
Program CMP_TS3 with value intended for TSIN[4]
Time Frame Interrupt
Next active pad = TSIN[5]
Program CMP_TS4 with value intended for TSIN[5]
Software workaround demonstration
1. During the initialization phase, program the CMP_TS[x] bit fields with the
left-shift factored in. Example: CMP_TS[0] for TSIN[1], CMP_TS[1] for
TSIN[2], ... CMP[7] for TSIN[0].
PMU_CM.001 Branch from non-cacheable to cacheable address space instruction may corrupt the program execution
Two consecutive instruction fetch accesses, the first to the non-cacheable and
the second to the cacheable address space may cause a corruption of the
program flow. If the error occurs, the cached instruction at the target address is
replaced with the opcode 0000_0000H instead of the opcode of the correct
instruction.
Conditions
One of the following cases may trigger the erroneous behavior:
1. In the normal program execution, a branch, function call or exception call
operation, with the current instruction executed from the non-cacheable
Flash address space and the branch target address in the cacheable Flash
address space.
2. The CPU generates a speculative fetch access to the ROM address space
when executing the BX LR instruction as an exception return to Thread
mode and using the Process Stack Pointer (PSP), but not using the
extended Floating-Point frame
(=> EXC_RETURN = FFFF_FFFDH stored in the Link Register LR; LR can
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be any GPR). This specualtive access is followed by an access to the
cacheable Flash address space (=> the access to the actual branch target
address).
Any of these cases results in two consecutive instruction fetch accesses in the
code address space with
•
•
the first an access to the non-cacheable Flash address space
(0C00_0000H − 0C0F_FFFFH or the ROM address space
(0000_0000H − 0000_3FFFH)
the second access in the cacheable Flash address space
(0800_0000H − 080F_FFFFH), to be serviced from the Instruction Buffer,
meaning the instruction is already stored in the Instruction Buffer of the
Prefetch Unit (already executed before and not displaced/invalidated later
in the program execution)
To see the problem from the normal program execution as described in the first
case, the code allocation must be mixed, with some code segments allocated
in the non-cacheable and other code segments in the cacheable address
space. In such an environment code branches between the different segments,
e.g. a function call from a cached thread to a function in the non-cacheable
address space which then returns back to the cached thread, may trigger the
problem.
In the second case, even if the complete application code is allocated in the
cacheable Flash address space, the CPU may generate a speculative fetch
access to the ROM address 0000_0000H, triggered by the BX LR instruction
and with EXC_RETURN = FFFF_FFFDH, as described above in operation 2.
System considerations
•
•
•
Only instruction fetches may trigger these accesses, data accesses are not
affected.
Instruction fetches to other address ranges than described above (e.g.
PSRAM, DSRAM) are also not subject to the problem.
The BX LR instruction can be used to return from regular functions and
exception handlers alike. When the LR contains a regular address, the CPU
will branch to that address. When LR contains a special EXC_RETURN
code, the CPU does an exception return instead, reading the target address
and restoring the processor status from the selected stack. The problem
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occurs only with EXC_RETURN = FFFF_FFFDH. Other system states result
in different return codes, e.g. Handler mode instead of Thread mode,
Floating Point state, or using the Main Stack Pointer use different
EXC_RETURN codes. With any other EXC_RETURN code than
FFFF_FFFDH the CPU does not generate the speculative access to the
address 0000_0000H, thus not generating the critical access sequence of a
non-cacheable access that is followed by a cacheable access.
Workaround
Allocate the complete code either in the cacheable or non-cacheable Flash
address space, do not use mixed code allocation. This workaround covers all
accesses out of the normal program flow. Equivalent to the allocation in the
non-cacheable address space with respect to reduced execution performance,
it is also possible to disable the Instruction Buffer with PREF_PCON.IBYP.
If the code is allocated in the cacheable Flash address space, the BX LR
instruction must not be executed with the exception return code
LR = FFFF_FFFDH.
It is possible to replace the BX LR instruction with the following sequence:
1. PUSH LR
2. POP PC
This sequence does not generate the speculative ROM access, thus it does not
generate the critical access sequence of a non-cacheable access that is
followed by a cacheable access.
If the application allows, the critical exception return code of the BX LR
instruction can be avoided by operating in different CPU state, e.g. if the
application does not use the Process Stack Pointer.
PORTS_CM.002 P0.9 Pull-up permanently active
A pull-up device on P0.9 is permanently active, disregarding any PORTS or
peripheral configurations.
This is not the standard pull device under control of the PORTS, but it is RUID_PU,
a part of the USB device detection circuitry of the USB.ID function, mapped to
P0.9. Its characteristic resistance is documented in the Data Sheet.
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Functional Deviations
Implications
This pull device may have adverse effects on currents drawn or driven, as well
as signal slopes and timings of the connected interfaces.
Workaround
None.
PORTS_CM.005 Different PORT register reset values after module reset
The PORTS registers can be reset independent of the reset of the system with
SCU_PRSET1.PPORTSRS. After such a module reset, some PORTS registers
have a reset value different to the reset value that is documented in the
Reference Manual.
Table 8
PORTS registers reset values
Register
Sytem reset value
Module reset value
Pn_IOCR8
0000 0000H
2020 2020H1)
Pn_PDISC
XXXX XXXXH2)
0000 0000H
Pn_PDR0
2222 2222H
0000 0000H
Pn_PDR1
2222 2222H
0000 0000H
1) Only in XMC4500 devices.
2) Device and package dependent
Implications
The different value in Pn_IOCR8 configures the respective port pins Pn.[11:8]
as inverted inputs instead of direct inputs. User software in Priviledged Mode
can reconfigure them as needed by the application.
With the different value in Pn_PDISC of the digital ports the availability of digital
pins in a device can no longer be verified via this register. Note that Pn_PDISC
of pure digital ports is read-only; user software can’t write to them.
The Pn_PDISC of the shared analog/digital port pins (P14 and P15)
enables/disables the digital input path. After a system reset this path is
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disabled, after a module reset enabled. User software in Priviledged Mode can
reconfigure them as needed by the application.
The different value in the Pn_PDR registers configures output port pins with a
“Strong-Sharp” output driver mode, as opposed to “Strong-Soft” driver mode
after a system reset. This may result in a higher current consumption and more
noise induced to the external system. User software in Priviledged Mode can
reconfigure them as needed by the application.
Workaround
None.
POSIF_AI.001 Input Index signal from Rotary Encoder is not decoded
when the length is 1/4 of the tick period
Each POSIF module can be used as an input interface for a Rotary Encoder. It
is possible to configure the POSIF module to decode 3 different signals: Phase
A, Phase B (these two signals are 90° out of phase) and Index. The index signal
is normally understood as the marker for the zero position of the motor Figure 1.
phase A
phase A
phase B
phase B
Index/
marker
Index/
marker
Figure 18
Rotary Encoder outputs - Phase A, Phase B and Index
There are several types of Rotary Encoder when it comes to length of the index
signal:
•
•
length equal or bigger than 1 tick period
length equal or bigger than 1/2 tick period
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•
length equal or bigger than 1/4 tick period
When the index signal is smaller than 1/2 of the tick period, the POSIF module
is not able to decode this signal properly, Figure 2 - notice that the reference
edge of the index generation in this figure is the falling of Phase B, nevertheless
this is an example and depending on the encoder type, this edge may be one
of the other three.
Due to this fact it is not possible to use the POSIF to decode these type of
signals (index with duration below 1/2 of the tick period).
Tick period (Tp)
Phase A
Phase B
Index
T i < ½ Tp
Figure 19
Different index signal types
Workaround
To make usage of the Index signal, when the length of this signal is less than
1/2 of the tick period, one should connect it directly to the specific counter/timer.
This connection should be done at port level of the device (e.g. connecting the
device port to the specific Timer/Counter(s)), Figure 3.
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Phase A
Up or dow count
Phase B
POSIF
Index
CCU4
Timer/
counter
Index
a)
Phase A
Up or dow count
Phase B
POSIF
CCU4
Timer/
counter
Index
b)
Figure 20
Index usage workaround - a) Non working solution; b)
Working solution
SCU_CM.006 Deep sleep entry with PLL power-down option generates
SOSCWDGT and SVCOLCKT trap
Entering the deep sleep mode with PLL power-down option (selected in
DSLEEPCR register of SCU module) may result with system traps triggered by
PLL watchdog (the SOSCWDGT trap) and/or loss-of-lock (the SVCOLCKT
trap).
Implications
Occurrence of one of the enabled traps will result in an immediate wake-up from
the deep sleep state, i.e. the deep sleep is effectively not entered.
Workaround
Disable SOSCWDGT and SVCOLCKT trap generation in TRAPDIS register of
SCU before entering deep sleep mode with PLL power-down option selected.
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Functional Deviations
SCU_CM.015 Parity Memory Test function not usable
The device provides an interface to access the parity bits of the contained
memories. The interface is based on using SCU registers PMTPR and PMTSR.
Due to synchronization issues wrong results will be produced.
Implications
The Parity Memory Test function is not usable.
Workaround
None.
STARTUP_CM.001 CAN Bootstrap Loader
The oscillator start up detection by device firmware does not check for a
required stable frequency lock. Therefore is not possible to support an entire
spectrum of standard XTAL input frequencies in the CAN BSL boot mode. As a
result the device may not answer the initial CAN frame.
Workaround
None.
USIC_AI.008 SSC delay compensation feature cannot be used
SSC master mode and complete closed loop delay compensation cannot be
used. The bit DX1CR.DCEN should always be written with zero to disable the
delay compensation.
Workaround
None.
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Functional Deviations
USIC_AI.010 Minimum and maximum supported word and frame length in
multi-IO SSC modes
The minimum and maximum supported word and frame length in multi-IO SSC
modes are shown in the table below:
Table 9
Multi-IO SSC Modes Word Length (bits)
Minimum
Frame Length (bits)
Maximum
Minimum
Maximum
Dual-SSC
4
16
4
64
Quad-SSC
8
16
8
64
Workaround
If a frame length greater than 64 data bits is required, the generation of the
master slave select signal by SSC should be disabled by PCR.MSLSEN.
To generate the master slave select signal:
•
•
Configure the same pin (containing the SELOx function) to general purpose
output function instead by writing 10000B to the pin’s input/output control
register (Pn_IOCRx.PCy); and
Use software to control the output level to emulate the master slave select
signal
This way, multiple frames of 64 data bits can be made to appear as a single
much larger frame.
USIC_AI.013 SCTR register bit fields DSM and HPCDIR are not shadowed
with start of data word transfer
The bit fields DSM and HPCDIR in register SCTR are not shadowed with the
start of a data word transfer.
Workaround
If the transfer parameters controlled by these bit fields need to be changed for
the next data word, they should be updated only after the current data word
transfer is completed, as indicated by the transmit shift interrupt PSR.TSIF.
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USIC_AI.014 No serial transfer possible while running capture mode timer
When the capture mode timer of the baud rate generator is enabled
(BRG.TMEN = 1) to perform timing measurements, no serial transmission or
reception can take place.
Workaround
None.
USIC_AI.015 Wrong generation of FIFO standard transmit/receive buffer
events when TBCTR.STBTEN/RBCTR.SRBTEN = 1
Transmit FIFO buffer modes selected by TBCTR.STBTEN = 1 generates a
standard transmit buffer event whenever TBUF is loaded with the FIFO data or
there is a write to INxx register, except when TRBSR.TBFLVL = TBCTR.LIMIT.
This is independent of TBCTR.LOF setting.
Similarly, receive FIFO buffer modes selected by RBCTR.SRBTEN = 1
generates a standard receive buffer event whenever data is read out from FIFO
or received into the FIFO, except when TRBSR.RBFLVL = RBCTR.LIMIT. This
is independent of RBCTR.LOF setting.
Both cases result in the wrong generation of the standard transmit and receive
buffer events and interrupts, if interrupts are enabled.
Workaround
Use only the modes with TBCTR.STBTEN and RBCTR.SRBTEN = 0.
USIC_AI.016 Transmit parameters are updated during FIFO buffer bypass
Transmit Control Information (TCI) can be transferred from the bypass structure
to the USIC channel when a bypass data is loaded into TBUF. Depending on
the setting of TCSR register bit fields, different transmit parameters are updated
by TCI:
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Functional Deviations
•
•
•
•
•
When SELMD = 1, PCR.CTR[20:16] is updated by BYPCR.SELO
(applicable only in SSC mode)
When WLEMD = 1, SCTR.WLE and TCSR.EOF are updated by
BYPCR.BWLE
When FLEMD = 1, SCTR.FLE[4:0] is updated by BYPCR.BWLE
When HPCMD = 1, SCTR.HPCDIR and SCTR.DSM are updated by BHPC
When all of the xxMD bits are 0, no transmit parameters will be updated
However in the current device, independent of the xxMD bits setting, the
following are always updated by the TCI generated by the bypass structure,
when TBUF is loaded with a bypass data:
•
•
•
WLE, HPCDIR and DSM bits in SCTR register
EOF and SOF bits in TCSR register
PCR.CTR[20:16] (applicable only in SSC mode)
Workaround
The application must take into consideration the above behaviour when using
FIFO buffer bypass.
USIC_AI.017 Clock phase of data shift in SSC slave cannot be changed
Setting PCR.SLPHSEL bit to 1 in SSC slave mode is intended to change the
clock phase of the data shift such that reception of data bits is done on the
leading SCLKIN clock edge and transmission on the other (trailing) edge.
However, in the current implementation, the feature is not working.
Workaround
None.
USIC_AI.018 Clearing PSR.MSLS bit immediately deasserts the SELOx
output signal
In SSC master mode, the transmission of a data frame can be stopped explicitly
by clearing bit PSR.MSLS, which is achieved by writing a 1 to the related bit
position in register PSCR.
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This write action immediately clears bit PSR.MSLS and will deassert the slave
select output signal SELOx after finishing a currently running word transfer and
respecting the slave select trailing delay (Ttd) and next-frame delay (Tnf).
However in the current implementation, the running word transfer will also be
immediately stopped and the SELOx deasserted following the slave select
delays.
If the write to register PSCR occurs during the duration of the slave select
leading delay (Tld) before the start of a new word transmission, no data will be
transmitted and the SELOx gets deasserted following Ttd and Tnf.
Workaround
There are two possible workarounds:
•
•
Use alternative end-of-frame control mechanisms, for example, end-offrame indication with TSCR.EOF bit.
Check that any running word transfer is completed (PSR.TSIF flag = 1)
before clearing bit PSR.MSLS.
USIC_AI.019 First data word received by IIC receiver triggers RIF instead
of AIF
When operating in IIC mode as a master or slave receiver, the first data word
received following a start condition and address match triggers a receive event
(indicated by PSR.RIF flag) instead of an alternate receive event (indicated by
PSR.AIF flag).
Workaround
To determine if a received data word is the first word of a new frame, bit 9 of
RBUF needs to be read:
•
•
When RBUF[9] is 1, the first data word of a new frame is indicated;
When RBUF[9] is 0, subsequent data words of the frame are indicated.
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Functional Deviations
USIC_AI.020 Handling unused DOUT lines in multi-IO SSC mode
In multi-IO SSC mode, when the number of DOUT lines enabled through the bit
field CCR.HPCEN is greater than the number of DOUT lines used as defined in
the bit field SCTR.DSM, the unused DOUT lines output incorrect values instead
of the passive data level defined by SCTR.PDL.
Implications
Unintended edges on the unused DOUT lines.
Workaround
To avoid unintended edges on the unused DOUT lines, it is recommended to
use the exact number of DOUT lines as enabled by the hardware controlled
interface during a multi-IO data transfer.
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Application Hints
3
Application Hints
The errata in this section describe application hints which must be regarded to
ensure correct operation under specific application conditions.
ADC_AI.H004 Completion of Startup Calibration
Before using the VADC the startup calibration must be completed.
The calibration is started by setting GLOBCFG.SUCAL. The active phase of the
calibration is indicated by GxARBCFG.CAL = 1. Completion of the calibration is
indicated by GxARBCFG.CAL = 0.
When checking for bit CAL = 1 immediately after setting bit SUCAL, bit CAL
might not yet be set by hardware. As a consequence the active calibration
phase may not be detected by software.The software may use the following
sequence for startup calibration:
1. GLOBCFG.SUCAL = 1
2. Wait for GxARBCFG.CAL = 1
3. Check for GxARBCFG.CAL = 0 before starting a conversion
Make sure that steps 1 and 2 of this sequence are not interrupted to avoid a
deadlock situation with waiting for GxARBCFG.CAL = 1.
ADC_TC.H011 Bit DCMSB in register GLOBCFG
The default setting for bit DCMSB (Double Clock for the MSB Conversion) in
register GLOBCFG is 0B, i.e. one clock cycle for the MSB conversion step is
selected.
DCMSB = 1B is reserved in future documentation and must not be used.
MultiCAN_AI.H005 TxD Pulse upon short disable request
If a CAN disable request is set and then canceled in a very short time (one bit
time or less) then a dominant transmit pulse may be generated by MultiCAN
module, even if the CAN bus is in the idle state.
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Application Hints
Example for setup of the CAN disable request:
Workaround
Set all INIT bits to 1 before requesting module disable.
MultiCAN_AI.H006 Time stamp influenced by resynchronization
The time stamp measurement feature is not based on an absolute time
measurement, but on actual CAN bit times which are subject to the CAN
resynchronization during CAN bus operation.The time stamp value merely
indicates the number of elapsed actual bit times. Those actual bit times can be
shorter or longer than nominal bit time length due to the CAN resynchronization
events.
Workaround
None.
MultiCAN_AI.H007 Alert Interrupt Behavior in case of Bus-Off
The MultiCAN module shows the following behavior in case of a bus-off status:
REC=0x1,
TEC=0x1
BOFF
INIT
TEC=0x60 or
REC=0x60
EWRN
Figure 21
REC=0x60,
TEC=0x1
EWRN+BOFF
INIT
REC=0x0,
TEC=0x0
ALERT
INIT
Alert Interrupt Behavior in case of Bus-Off
When the threshold for error warning (EWRN) is reached (default value of Error
Warning Level EWRN = 0x60), then the EWRN interrupt is issued. The bus-off
(BOFF) status is reached if TEC > 255 according to CAN specification,
changing the MultiCAN module with REC and TEC to the same value 0x1,
setting the INIT bit to 1B, and issuing the BOFF interrupt. The bus-off recovery
phase starts automatically. Every time an idle time is seen, REC is incremented.
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Application Hints
If REC = 0x60, a combined status EWRN+BOFF is reached. The corresponding
interrupt can also be seen as a pre-warning interrupt, that the bus-off recovery
phase will be finished soon. When the bus-off recovery phase has finished (128
times idle time have been seen on the bus), EWRN and BOFF are cleared, the
ALERT interrupt bit is set and the INIT bit is still set.
MultiCAN_AI.H008 Effect of CANDIS on SUSACK
When a CAN node is disabled by setting bit NCR.CANDIS = 1B, the node waits
for the bus idle state and then sets bit NSR.SUSACK = 1B.
However, SUSACK has no effect on applications, as its original intention is to
have an indication that the suspend mode of the node is reached during
debugging.
MultiCAN_TC.H003 Message may be discarded before transmission in
STT mode
If MOFCRn.STT=1 (Single Transmit Trial enabled), bit TXRQ is cleared
(TXRQ=0) as soon as the message object has been selected for transmission
and, in case of error, no retransmission takes places.
Therefore, if the error occurs between the selection for transmission and the
real start of frame transmission, the message is actually never sent.
Workaround
In case the transmission shall be guaranteed, it is not suitable to use the STT
mode. In this case, MOFCRn.STT shall be 0.
MultiCAN_TC.H004 Double remote request
Assume the following scenario: A first remote frame (dedicated to a message
object) has been received. It performs a transmit setup (TXRQ is set) with
clearing NEWDAT. MultiCAN starts to send the receiver message object (data
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Application Hints
frame), but loses arbitration against a second remote request received by the
same message object as the first one (NEWDAT will be set).
When the appropriate message object (data frame) triggered by the first remote
frame wins the arbitration, it will be sent out and NEWDAT is not reset. This leads
to an additional data frame, that will be sent by this message object (clearing
NEWDAT).
There will, however, not be more data frames than there are corresponding
remote requests.
r e m o te
re q u e s t
C AN Bus
r e m o te
re q u e s t
d a ta
d a ta
lo s s o f
a rb itra tio n
s e tu p
M u ltiC A N
d a ta
o b je c t
c le a r
NEW DAT
by H W
Figure 22
s e tu p
c le a r s e t
NEW DAT
by H W
d a ta
o b je c t
d a ta
s e tu p
o b je c t
c le a r
NEW DAT
by H W
Loss of Arbitration
RESET_CM.H001 Power-On Reset Release
The on-chip EVR implements a power validation circuitry which supervises
VDDP and VDDC. This circuit releases or asserts the system reset to ensure
safe operation. This reset is visible on bidirectional PORST pin.
Implications
Potential effects if the PORST release requirement is not met (please refer to
the Data Sheet for details) is presence of spikes or toggling on the PORST pin
which may have an effect on the rest of the system if the reset signal is shared
with other electronic components on the PCB. A repeated PORST may also
result in loss of information about hibernation status after an interrupted wake-
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Application Hints
up has been performed. Potential presence of the spikes on PORST, however,
will not lead to a fatal system startup failure or deadlock.
Recommendation
It is required to ensure fast PORST release, as specified in Data Sheet. The
recommended approach is to apply a pull-up resistor on the PORST pin.
Typically a 10 - 90 kΩ resistor is sufficient in application cases where the device
is in control of the reset generation performed by its internal power validation
circuit and no additional load is applied to the PORST pin. The required pull-up
resistor value may vary depending on the electrical parameters of the system,
like parasitic wire resistance and capacitance of the PCB, driving strength of
other electronic components connected to the PORST pin and other side
conditions. The pull-up resistance may need to be adapted accordingly.
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