ST71XX with S29GL512P STB Application POR Issues AN

ST71XX with S29GL512P STB Application POR Issues AN
ST71xx with S29GL512P in STB
Application Power On Reset Issue
Application Note
by Victor Li
1. Introduction
The STi71xx family of STMicroelectronics MPEG2/MPEG4 processors is widely used in high definition set top
box solutions made in China. STi71xx normally requires NOR flash density of 128 Mbits and up on its EMI as
external memory.
One of the most common, and easily overlooked, issue with NOR flash applications is Power-On-Reset.
Spansion® GL-P products need longer RESET times than the older GL-N serial family. This document uses
our customer, Jiuzhou, as a case study to discuss the Power-On-Reset issue when using Spansion’s GL-P
products. (Note: Jiuzhou is one of China’s largest STB R&D and manufacturing companies.)
2. Detailed Failure Symptoms
Jinzhou’s application uses the ST7167 with our S29GL512P11TFI010. Jinzhou reported that a few units
failed STB boot up due to high temperatures, and the failure rate was about 1%. There was no erasing and
programming involved, only read operations took place during the system boot up process.
As an additional check, Jiuzhou did checksum testing, it was found that checksum testing failed easily at high
temperatures. In addition, a scope (Figure 2.1) was used to check the CE#, OE# timing was 270 ns. No
access time issue was found.
The Reset timing was double checked , when VCC = 2.7V, Reset power was already 2V. The issue seemed to
be that there was not enough reset time.
Figure 2.1 Scope Screen Shot
Publication Number ST71XX_with_S29GL512P_STB_Application_POR_Issues_AN
Revision 01
Issue Date July 11, 2011
App l ic atio n
No t e
Spansion’s GL-P Reset needs the RESET# pin to go low for at least 35 µs when VCC > 2.7V and stable. It
was determined that Jiuzhou’s resistor-capacitor (10 kΩ and 0.1 nF) time reset was not enough.
Table 2.1 shows the detailed GL-P power-on-reset requirement.
Table 2.1 S29GL-P Hardware Reset (RESET#) Operation
Parameter
JEDEC
Std.
Description
Speed
Unit
Min
35
µs
RESET# Pin Low (NOT During Embedded Algorithms) to
Read Mode or Write mode
Min
35
µs
tRP
RESET# Pulse Width
Min
35
µs
tReady
RESET# Pin Low (During Embedded Algorithms) to Read
Mode or Write mode
tReady
tRH
Reset High Time Before Read
Min
200
ns
tRPD
RESET# Low to Standby Mode
Min
10
µs
tRB
RY/BY# Recovery Time
Min
0
ns
Figure 2.2 Reset Timings
RY/BY#
CE#, OE#
tRH
RESET#
tRP
tReady
Reset Timings NOT during Embedded Algorithms
Reset Timings during Embedded Algorithms
tReady
RY/BY#
tRB
CE#, OE#
RESET#
tRP
3. Correction Action
Jiuzhou changed the resistor-capacitor reset parameter to 10 kΩ and 4.7 µF. Retesting at Jiuzhou factory,
with the ST7167 with S29GL512P11TFI010 application, found no abnormal results . The Reset timing now
matches the GL-P 35 µs requirement.
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ST71XX_with_S29GL512P_STB_Application_POR_Issues_AN_01
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4.
Note
Conclusion
The specification for hardware reset timing and reset current has changed.
However, this change has been proven to be of minimal impact on the customers, since many common
processors support these parameters. See Table 4.1 for the detailed parameter change. Also, consult the
S29GL-P data sheet for advanced information on Hardware Reset Timing for future 65 nm S29GL-R family of
products.
Table 4.1 Comparison of Hardware Reset Timings
Parameter
Description
JEDEC
3
S29GL-N
S29GL-P
Std.
tREADY
RESET# Pin Low (During Embedded Algorithms) to
Read or Write Mode
20 ns
35 µs
tREADY
RESET# Pin Low (NOT During Embedded
Algorithms) to Read or Write Mode
500 ns
35 µs
tRP
RESET# Pulse Width
500 ns
35 µs
tRH
RESET# High Time Before Read
50 ns
200 ns
tRB
RY/BY# Recovery Time
0 ns
0 ns
1 µA (Typ)
250 µA (Typ)
ICC5
VCC RESET# Current
ST71XX_with_S29GL512P_STB_Application_POR_Issues_AN_01
5 µA (Max)
July 11, 2011
App l ic atio n
No t e
5. Revision History
Section
Description
Revision 01 (July 11, 2011)
Initial release
July 11, 2011
ST71XX_with_S29GL512P_STB_Application_POR_Issues_AN_01
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A pplication
Note
Colophon
The products described in this document are designed, developed and manufactured as contemplated for general use, including without
limitation, ordinary industrial use, general office use, personal use, and household use, but are not designed, developed and manufactured as
contemplated (1) for any use that includes fatal risks or dangers that, unless extremely high safety is secured, could have a serious effect to the
public, and could lead directly to death, personal injury, severe physical damage or other loss (i.e., nuclear reaction control in nuclear facility,
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any use where chance of failure is intolerable (i.e., submersible repeater and artificial satellite). Please note that Spansion will not be liable to
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devices have an inherent chance of failure. You must protect against injury, damage or loss from such failures by incorporating safety design
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