Controller Area Network (CAN)

Controller Area Network (CAN)
®
PSoC Creator™ Component Datasheet
Controller Area Network (CAN)
2.0
Features
 CAN2.0 A/B protocol implementation, ISO 11898-1 compliant
 Programmable bit rate up to 1 Mbps at 8 MHz (BUS_CLK)
 Two- or three-wire interface to external transceiver (Tx, Rx, and Enable)
 Extended hardware message filter that covers Data Byte 1 and Data Byte 2 fields
 Programmable transmit priority: Round Robin and Fixed
 CAN component is not supported on PSoC 5
General Description
The Controller Area Network (CAN) controller implements the CAN2.0A and CAN2.0B
specifications as defined in the Bosch specification and conforms to the ISO-11898-1 standard.
When to Use a CAN
The CAN protocol was originally designed for automotive applications with a focus on a high
level of fault detection. This ensures high communication reliability at a low cost. Because of its
success in automotive applications, CAN is used as a standard communication protocol for
motion-oriented machine-control networks (CANOpen) and factory automation applications
(DeviceNet). The CAN controller features allow you to efficiently implement higher-level
protocols, without affecting the performance of the microcontroller CPU.
Input/Output Connections
This section describes the various input and output connections for the CAN Component. An
asterisk (*) in the list of I/Os indicates that the I/O may be hidden on the symbol under the
conditions listed in the description of that I/O.
rx – Input
CAN bus receive signal (connected to CAN Rx bus of external transceiver).
Cypress Semiconductor Corporation • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600
Document Number: 001-71391 Rev. *A
Revised November 11, 2011
Controller Area Network (CAN)
®
PSoC Creator™ Component Datasheet
tx– Output
CAN bus transmit signal, (connected to CAN Tx bus of external transceiver).
tx_en – Output *
External transceiver enable signal. This output displays when the Add Transceiver Enable
Signal option is selected in the Configure dialog.
interrupt – Output *
The interrupt output is driven by the interrupt sources configured in the CAN hardware. All
sources are ORed together to create the final output signal. The sources of the interrupt can be:

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Message Transmitted
Message Received
Receive Buffer Full
Bus Off State
CRC Error Detected
Message Format Error Detected
Message Acknowledge, Error Detected
Bit Stuffing Error Detected
Bit Error Detected
Overload Frame Received
Arbitration Lost Detected
This output displays when the Enable External Interrupt Line option is selected in the
Advanced Interrupt Configuration… window of the Interrupt tab of the Configure dialog.
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PSoC Creator™ Component Datasheet
Controller Area Network (CAN)
Schematic Macro Information
The default CAN in the Component Catalog is a schematic macro using a CAN component with
default settings. The CAN component is connected to an Input and an Output Pins component.
The Pins components are also configured with default settings, except that Input Synchronized is
set to false in the Input Pin component.
Component Parameters
Drag a CAN component onto your design and double-click it to open the Configure dialog. This
dialog has several tabs to guide you through the process of setting up the CAN component.
Component Update Note
If updating the CAN component from a previous version, many of the parameters have been
given a new format and must be converted. To do so, open the Configure dialog, change at
least one parameter option, and click OK to save the change.
General Tab
The General tab contains the following settings:
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Controller Area Network (CAN)
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PSoC Creator™ Component Datasheet
Add Transceiver Enable Signal
Enables or disables the use of the tx_en signal for the external CAN transceiver. Enabled by
default.
Transmit Buffer Arbitration
Defines the message transmission arbitration scheme:

Round Robin (default) – Buffers are served in a defined order: 0-1-2 ... 7-0-1. A particular
buffer is only selected if its TxReq flag is set. This scheme guarantees that all buffers receive
the same probability to send a message.

Fixed priority – Buffer 0 has the highest priority. This way it is possible to designate buffer 0
as the buffer for error messages and guarantee that they are sent first.
Bus-Off Restart
Used to configure the reset type:

Manual (default) – After the bus is turned off, you must restart the CAN. This is the
recommended setting.

Automatic – After the bus is turned off, the CAN controller restarts automatically after 128
groups of 11 recessive bits.
CAN Bus Synchronization Logic
Used to configure edge synchronization:
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‘R’ to ‘D’ (default) – Edge from ‘R’(recessive) to ‘D’(dominant) is used for synchronization
Both edges – Both edges are used for synchronization
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PSoC Creator™ Component Datasheet
Controller Area Network (CAN)
Timing Tab
The Timing tab contains the following settings:
Settings

BRP – Bit Rate Prescaler value for generating the time quantum. The bit timing calculator is
used to calculate this value. 0 indicates 1 clock; 7FFFh indicates 32767 clock cycles, 15 bits.


Tseg1 – Value of time segment 1.
Tseg2 – Value of time segment 2. Values 0 and 1 are not allowed; 2 is only allowed when
Sample Mode is set to direct sampling (1-Sample).
The following shows the CAN bit timing representation:
Nominal Bit Time = 8...25 TQ (Time Quanta)
SJW: 1...4TQ
Tseg1
prop_seg + phase_seg1
Synchronization
Segment
Document Number: 001-71391 Rev. *A
Tseg2
phase_seg2
Sample Point
1 or 3 Sample Mode
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Controller Area Network (CAN)
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PSoC Creator™ Component Datasheet
Calculator
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Clock Frequency (in MHz) – The system clock frequency equal to BUS_CLK.
Desired Baud Rate (in Kbps) – Options are: 10, 20, 62.5, 125, 250, 500, 800, or 1000.
SJW – Configuration of synchronization jump width (2 bits). The value must be less than or
equal to Tseg1 and less than or equal to Tseg2. Options are: 1, 2, 3, or 4.
Sample Mode – Configuration of sampling mode. Options are: 1-Sample or 3-Sample.
Table
Bit timing is calculated, and the proposed register settings for time segments (Tseg1 and Tseg2)
and BRP are displayed in the parameter table. You can select the values to be loaded by
double-clicking the appropriate row. Selected values are displayed in the top Settings input
boxes.
You may also choose to manually enter values for Tseg1, Tseg2, and BRP in the provided input
boxes.
Note Incorrect bit timing settings might cause the CAN controller to remain in an error state.
The following diagram shows an example of how all timing is derived from the oscillator.
Bit Time Segments
SYNC SEG (Synchronization Segment)
This part of the bit time is used to synchronize the various nodes on the bus. An edge is
expected to lie within this segment.
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PSoC Creator™ Component Datasheet
Controller Area Network (CAN)
PROP SEG (Propagation Time Segment)
This part of the bit time is used to compensate for the physical delay times within the network. It
is twice the sum of the signal's propagation time on the bus line, the input comparator delay, and
the output driver delay.
PHASE SEG1, PHASE SEG2 (Phase Buffer Segment1/2)
These phase-buffer segments are used to compensate for edge phase errors. These segments
can be lengthened or shortened by resynchronization.
Sample Point
The sample point is the point in time at which the bus level is read and interpreted as the value
of that respective bit. It is located at the end of PHASE_SEG1.
Information Processing Time
The information processing time is the time segment starting with the sample point reserved for
calculating the subsequent bit level.
Time Quantum
The time quantum is a fixed unit of time derived from the oscillator period. There is a
programmable prescaler (BRP), with integral values, ranging from 1 to 32767. Starting with the
minimum time quantum, the time quantum can have a length of
TIME QUANTUM = m × MINIMUM TIME QUANTUM
where m is the value of the prescaler.
Length of Time Segments
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SYNC_SEG is 1 time quantum long.
PROP_SEG is programmable to be 1, 2, …, 8 time quanta long.
PHASE_SEG1 is programmable to be 1, 2, ..., 8 time quanta long.
PHASE_SEG2 is the maximum of PHASE_SEG1 and the information processing time
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Controller Area Network (CAN)
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PSoC Creator™ Component Datasheet
Interrupt Tab
Basic Interrupt Configuration
The Basic Interrupt Configuration tab contains the following settings:
Enable Interrupts
Enable or disable global interrupts from the CAN Controller. Enabled by default.
Enabled – Global interrupts are enabled when the CAN component is started using CAN_Start().
Disabled – Global interrupts are not enabled when the CAN component is started using
CAN_Start(). The CAN ISR is not entered until the global interrupt enable bit is set. It is your
responsibility to enable or disable global interrupts in main code, using CAN_GlobalIntEnable()
or CAN_GlobalIntDisable().
Message Transmitted
Enable or disable message transmitted interrupts. Disabled by default. Indicates that a message
was sent. When disabling the Message Transmitted interrupt, the CAN displays the following
message: Do you wish to disable all Transmit Buffers Interrupts?

Yes – Uncheck the Message Transmitted check box, and uncheck all individual transmit
buffer interrupts on the Transmit Buffers tab.

No (default) – Uncheck the Message Transmitted check box, and keep all individual
transmit buffer interrupts on the Transmit Buffers tab as they are.

Cancel – No changes are made.
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PSoC Creator™ Component Datasheet
Controller Area Network (CAN)
Message Received
Enable or disable message received interrupts. Enabled by default. Indicates that a message
was received. When disabling the Message Received interrupt, the CAN displays the following
message: Do you wish to disable all Receive Buffers Interrupts?

Yes (default) – Uncheck the Message Received check box, and uncheck all individual
receive buffer interrupts on the Receive Buffers tab.

No – Uncheck the Message Received check box, and keep all individual receive buffer
interrupts on the Receive Buffers tab as they are.

Cancel – No changes are made.
Receive Buffer Full
Enable or disable message lost interrupt. Indicates that a new message was received when the
previous message was not acknowledged. Disabled by default.
Bus Off State
Enable or disable Bus Off interrupt. Indicates that the CAN node has reached the Bus Off state.
Enabled by default.
CRC Error Detected
Enable or Disable CRC error interrupt. Indicates that a CAN CRC error was detected. Disabled
by default.
Message Format Error Detected
Enable or disable message format error interrupt. Indicates that a CAN message format error
was detected. Disabled by default.
Message Acknowledge Error Detected
Enable or disable message acknowledge error interrupt. Indicates that a CAN message
acknowledge error was detected. Disabled by default.
Bit Stuffing Error Detected
Enable or disable bit stuffing error interrupt. Indicates that a bit stuffing error was detected.
Disabled by default.
Bit Error Detected
Enable or disable bit error interrupt. Indicates that a bit error was detected. Disabled by default.
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Controller Area Network (CAN)
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PSoC Creator™ Component Datasheet
Overload Frame Received
Enable or disable overload interrupt. Indicates that an overload frame was received. Disabled by
default.
Arbitration Lost Detected
Enable or disable managing arbitration and cancellation of queued messages. Indicates that the
arbitration was lost while sending a message. Disabled by default.
Advanced Interrupt Configuration
The Advanced Interrupt Configuration tab contains the following settings:
Enable External Interrupt Line
Enable external visibility and connectivity of the CAN block interrupt line. Default is cleared
(external interrupt line not visible in the CAN component symbol instance).
Disable Internal ISR
Disable or bypass internal ISR component. If the internal ISR is disabled, the relevant CAN APIs
do not handle the ISR start/stop processes. Default is cleared (internal ISR is enabled). The
check box is available (not grayed out) only if Enable External Interrupt Line is selected. You
can disable the internal ISR only if there is an alternate provision (external interrupt line) to
handle interrupts.
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PSoC Creator™ Component Datasheet
Controller Area Network (CAN)
Full Custom Internal ISR
Enable the use of the internal ISR with fully custom code. When this option is selected, the
CAN_ISR contains no code other than the optional PSoC3 ES1/ES2 ISR patch. Put your custom
code between the lines:
/* Place your Interrupt code here. */
/* `#START CAN_ISR` */
/* `#END` */
Default is unselected (default to CAN v1.50 ISR handling). The check box is available (not
grayed out) only if Disable Internal ISR is not selected.
ISR Helper Function Call
If only basic interrupt settings are used (for example, as in CAN v1.50), when an interrupt occurs,
the CAN ISR calls relevant user-customizable functions (ISR helpers) based on the enabled
interrupts.
These options give you the opportunity to enable or disable ISR helper calls, so that custom
handling of specific interrupts can be implemented both in hardware and firmware. Default is
Enable. These options are available (not grayed out) if the relevant interrupt event is enabled
AND Full Custom Internal ISR is not checked AND Disable Internal ISR is not checked.
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Controller Area Network (CAN)
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PSoC Creator™ Component Datasheet
Receive Buffers Tab
The Receive Buffers tab contains the following settings:
Mailbox
A receive mailbox is disabled until Full or Basic is selected. The IDE, ID, RTR, RTRreply and
IRQ fields are locked for all disabled mailboxes.
For Full mailboxes, the Mailbox field is editable to enter a unique message name. The API
provided for handling each mailbox will have the mailbox string appended. Accepted symbols
are: A–Z, a–z, 0–9, and _. If you enter an incorrect name, an error message displays and the
Mailbox field returns to the default value.
Full
When Full is selected, you can modify the Mailbox, IDE, ID, RTR, RTRreply, IRQ and Linking
fields. Default selections are placed with the following options:
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Mailbox = Mailbox number 0 to 15
IDE = Cleared
ID = 0x001
RTR = Cleared
RTRreply = Cleared and locked (only enable when RTR is selected)
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PSoC Creator™ Component Datasheet
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Controller Area Network (CAN)
IRQ = Selected, only available if Message Received (Interrupt tab) interrupt is selected
Linking = Cleared
Basic
If Basic is selected, the options IDE, ID, RTR, RTRreply are unavailable. Default selections are
placed with the following options:
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IDE = Cleared (unavailable)
ID = <All> (unavailable)
RTR = Cleared (unavailable)
RTRreply = Cleared (unavailable)
IRQ = Cleared, only available if Message Received interrupt is selected
Linking = Cleared
IDE
When the IDE box is cleared the identifier is limited to 11 bits (0x001 to 0x7FE). When IDE is
selected the identifier is limited to 29 bits (0x00000001 to 0x1FFFFFFE).
RTR - Remote Transmission Request
Only available for mailboxes set up to receive Full CAN messages. When selected, it configures
the acceptance filter settings to only allow receipt of messages whose RTR bit is set.
RTRreply - Remote Transmission Request Auto Reply
Only available for mailboxes set up to receive Full CAN messages, with the RTR bit set. When
checked, it automatically replies to an RTR request with the content of the receive buffer.
IRQ
When enabling the IRQ for a mailbox, if the Message Received Interrupt in the Interrupt tab is
cleared, the following message is displayed: Global “Message Received Interrupt” is
disabled. Do you wish to enable it?

Yes – Select the IRQ check box and select the Message Received Interrupt check box on
the Interrupt tab.

No or Cancel – Select the IRQ check box and leave the Message Received Interrupt check
box in the Interrupt tab as is.
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Controller Area Network (CAN)
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PSoC Creator™ Component Datasheet
Linking
The Linking check box allows the linking of several sequential receive mailboxes to create an
array of receive mailboxes. This array acts like a receive FIFO. All mailboxes of the same array
must have the same message filter settings; that is, the acceptance mask register (AMR) and
acceptance code register (ACR) are identical.
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The last mailbox of an array may not have its linking flag set.
The last mailbox 15 cannot have its linking flag set.
All linked mailboxes are highlighted with the same color.
Only the first mailbox in the linked array is editable. All parameters are automatically applied
to all linked mailboxes within the same array.
One function is generated for all linked mailboxes.
Receive Message Functions
Every Full RX mailbox has a predefined API. The function list is available in the
CAN_1_TX_RX_func.c project file. These functions are conditionally compiled depending on the
receive mailbox setting. Only mailboxes defined as Full have their respective functions compiled.
The macro identifier CAN_1_RXx_FUNC_ENABLE defines whether a function is compiled.
Defines are listed in the CAN_1.h project file.

When a message received interrupt occurs, the CAN_MsgRXIsr() function is called. This
function loops through all receive mailboxes and checks their respective “Message Available
Flag” (MsgAv – Read: 0 No new message available; 1 New message available) and “Interrupt
Enable” (Receive Interrupt Enable: 0 Interrupt generation is disabled, 1 Interrupt generation is
enabled) for successful receipt of a CAN message.

If the Message Receive interrupt is enabled, then when a message is received the
CAN_ReceiveMsgX() function is called, where X indicates the Full CAN mailbox number or
user-defined name.

For all interrupt-based Basic CAN mailboxes, the CAN_ReceiveMsg(uint8 rxMailbox) function
is called, where the rxMailbox parameter indicates the number of the mailbox that received
the message.
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Controller Area Network (CAN)
Receive Buffers Configuration
The following is an example to illustrate the use of the receive message APIs.
CAN_1.h file:
…
#define CAN_1_RX0_FUNC_ENABLE 1
#define CAN_1_RX1_FUNC_ENABLE 0
#define CAN_1_RX2_FUNC_ENABLE 1
…
CAN_1_TX_RX_func.c file:
#if(CAN_1_RX0_FUNC_ENABLE)
void CAN_1_ReceiveMsg0(void)
{
/* `#START MESSAGE_0_RECEIVED` */
/* `#END` */
CAN_1_RX[0].rxcmd.byte[0] |= CAN_1_RX_ACK_MSG;
}
#endif
#if(CAN_1_RX1_FUNC_ENABLE)
void CAN_ReceiveMsg1(void)
{
/* `#START MESSAGE_1_RECEIVED` */
/* `#END` */
CAN_1_RX[1].rxcmd.byte[0] |= CAN_1_RX_ACK_MSG;
}
#endif
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Controller Area Network (CAN)
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PSoC Creator™ Component Datasheet
The following function will be called for CAN Receive Message 2, configured as Basic CAN with
interrupt enabled.
void CAN_ReceiveMsg(uint8 rxMailbox)
{
if (CAN_1_RX[rxMailbox].rxcmd.byte[0] & CAN_1_RX_ACK_MSG)
{
/* `#START MESSAGE_BASIC_RECEIVED` */
/* `#END` */
CAN_1_RX[rxMailbox].rxcmd.byte[0] |= CAN_1_RX_ACK_MSG;
}
}
CAN_1_INT.c file
void CAN_1_MsgRXIsr(void)
{
…
/* RX Full mailboxes handler */
switch(i)
{
case 0 : CAN_ReceiveMsg0();
break;
case 1 : CAN_ReceiveMsg1();
break;
default:
break;
}
…
}
If Linking is implemented, conditional compile applies to the mailbox with the IRQ flag set. All
receive functions acknowledge message receipt by clearing the Message Available (MsgAv) flag.
How to Set AMR and ACR to Accept Range of IDs
The following is the ACR/AMR register representation:
[31:3] – Identifier(ID[31:21] – identifier when IDE = 0, ID[31:3] - identifier
when IDE = 1), [2] – IDE, [1] – RTR, [0] – N/A;
The acceptance mask register (AMR) defines whether the incoming bit is checked against
acceptance code register (ACR).
AMR:
‘0’
The incoming bit is checked against the respective ACR. The message is not
accepted when the incoming bit doesn’t match the respective ACR bit.
‘1’
The incoming bit is doesn’t care.
For example, to set up the mailbox to receive a range of IDs of 0x180–187, IDE = 0 (cleared),
RTR = 0 (cleared), mailbox 5, perform the following additional actions:
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PSoC Creator™ Component Datasheet
Controller Area Network (CAN)
Take the low range of ID, for instance 0x180, and IDE and RTR accordingly. For this ID, IDE,
and RTR values, AMR and ACR registers are set to values:
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ACR[31:21] = 0x180
AMR[31:21] = 0x0
ACR[ 20:3] = 0x0
AMR[20:3] = 0x3FFFF (all ones)
ACR[2] = 0
AMR[2] = 0
ACR[1] = 0
AMR[1] = 0
ACR[0] = 0
AMR[0] = 0
Define common part of range ID (11bit):

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

0x180 = 0`b001 1000 0000
0x187 = 0`b001 1000 0111
Mask = 0`b001 1000 0XXX
ACR[31:21] = 0’b000 0000 0111
You must put 1s instead of “XXX” and nulls instead of common bits into the AMR register. So,
the next values are:





ACR[31:21] = 0x180
AMR[31:21] = 0x7;
ACR[ 20:3] = 0x0
AMR[20:3] = 0x3FFFF - all ones;
ACR[2] = 0
AMR[2] = 0
ACR[1] = 0
AMR[1] = 0
ACR[0] = 0
AMR[0] = 0
Use the CAN_RXRegisterInit() function to write AMR register of mailbox number 5:
uint8 result = FAIL;
uint16 temp_amr;
uint16 temp_acr;
/* Upper address value, so address is shifted */
temp_amr = (0x7 << 21);
/* obtain necessary value to put in AMR */
temp_acr = (0x180 << 21);
/* obtain necessary value to put in ACR */
if (CAN_RXRegisterInit(&CAN_1_RX[5].rxamr, temp_amr))
{
if ((CAN_RXRegisterInit(&CAN_1_RX[5].rxacr, temp_acr))
result = SUCCESS;
}
return result; /* error – if return no zero value; */
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PSoC Creator™ Component Datasheet
For additional details on AMR and ACR configuration, refer to the Controller Area Network (CAN)
chapter in the PSoC® 3 and PSoC 5® Technical Reference Manual.
Transmit Buffers Tab
The Transmit Buffers tab contains the following settings:
Mailbox
For Full mailboxes, the Mailbox field is editable and you can enter a unique name for a mailbox.
The function for handling this mailbox will also have a unique name. The accepted characters
are: A–Z, a–z, 0–9, and _. If you enter an incorrect name the Mailbox field, it reverts to the
default value.
Full
When Full is selected, you can modify the Mailbox, IDE, ID, RTR, RTRreply, IRQ, and Linking
fields. Default selections are placed with the following options:



Mailbox = Number 0 to 7
IDE = Cleared
ID = 0x01
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


Controller Area Network (CAN)
RTR = Cleared
DLC = 8
IRQ = Cleared
Basic
By default, the Basic check box is selected for all of the mailboxes. If Basic is selected, the
options ID, RTR, and DLC are unavailable. If Basic is selected, the required CAN message
fields should be entered using code. Default selections are placed with the following options:





IDE = Cleared
ID = Nothing (unavailable)
RTR = Cleared (unavailable)
DLC = 8 (unavailable)
IRQ = Cleared
IDE
If the IDE check box is cleared, the identifier cannot be greater than 11 bits (from 0x001 to
0x7FE). If IDE is selected, a 29-bit identifier is allowed (from 0x00000001 to 0x1FFFFFFE). You
cannot choose identifiers of 0x000 or 0x7FF (11-bit) or 0x1FFFFFFF (29 bit).
ID
The message identifier.
RTR
The message is a Return Transmission Request Message.
DLC
The number of bytes the message contains.
IRQ
The IRQ bit depends on Message Transmitted (Interrupt tab).
If the Message Transmitted check box is cleared, when selecting the IRQ, the message
appears: Global “Message Transmitted Interrupt” is disabled. Do you wish to enable it?

Yes – Select IRQ and the Message Transmitted Interrupt check box in the Interrupt tab.
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Controller Area Network (CAN)
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PSoC Creator™ Component Datasheet
No or Cancel – Select IRQ. The Message Transmitted Interrupt check box in the Interrupt
tab remains cleared.
CAN TX Functions
Every Full TX mailbox has a predefined API. The function list is available in the
CAN_1_TX_RX_func.c project file. These functions are conditionally compiled depending on the
transmit mailbox setting. Only mailboxes defined as Full will have their respective functions
compiled.
The macro identifier CAN_1_TXx_FUNC_ENABLE defines whether a function is compiled.
Defines are listed in the CAN_1.h project file.
The CAN_SendMsgX() function is provided for all Tx Mailboxes configured as Full, where X
indicates the Full CAN mailbox number or user-defined name.
Transmit Buffers Configuration
The following is an example to illustrate the use of the transmit APIs.
CAN_1.h file
#define CAN_1_TX0_FUNC_ENABLE 1
#define CAN_1_TX1_FUNC_ENABLE 0
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Controller Area Network (CAN)
CAN_1_TX_RX_func.c file
#if(CAN_1_TX0_FUNC_ENABLE)
uint8 CAN_1_SendMsg0(void)
{
uint8 result = SUCCESS;
if (CAN_1_TX[0u].txcmd.byte[0u] & CAN_1_TX_REQUEST_PENDING) ==
CAN_1_TX_REQUEST_PENDING)
{
result = CAN_FAIL;
}
else
{
/* `#START MESSAGE_0_TRANSMITTED` */
/* `#END` */
CY_SET_REG32((reg32 *) & CAN_1_TX[0u] |= txcmd CAN_SEND_MESSAGE);
}
return result;
}
#endif
The common function provided for all Basic Transmit mailboxes:
uint8 CAN_SendMsg(CAN_TX_MSG *message)
A generic structure is defined for the application used to assemble the required data for a CAN
transmit message:

ID – the restriction if the ID slot includes:
 For a standard message (IDE = 0) identifier limited to 11 bits (0x001 to 0x7FE).
 For an extended message (IDE = 1) identifier limited to 29 bits (0x00000001 to
0x1FFFFFFE)





RTR (0 – Standard message, 1 – 0xFF: RTR bit set in the message)
IDE (0 – Standard message, 1 – 0xFF: Extended message)
DLC (Defines number of data bytes 0 to 8, 9 to 0xFF equal 8 data bytes)
IRQ (0 – IRQ Enable, 1 – 0xFF: IRQ Disable)
DATA_BYTES (Pointer to structure of 8 bytes that represent transmit data)
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Controller Area Network (CAN)
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PSoC Creator™ Component Datasheet
When called, the CAN_SendMsg() function loops through the transmit message mailboxes that
are designated as Basic CAN mailboxes and looks for the first available mailbox:

When a free Basic CAN mailbox is found, the data passed through the CAN_TX_MSG
structure is copied to the appropriate CAN transmit mailbox. When the message is put into
transmit queue, an indication of “SUCCESS” is returned to the application.

When no free Basic mailbox is found, the function tries again for a limited number of retries
(up to three). When all retries fail, an indication of “FAIL” is returned to the application.
The CAN_TX_MSG structure contains all information required to transmit a message:
typedef struct _CAN_TX_MSG
{
uint32 id;
uint8 rtr;
uint8 ide;
uint8 dlc;
uint8 irq;
CAN_DATA_BYTES_MSG *msg;
} CAN_TX_MSG;
The CAN_DATA_BYTES structure contains eight bytes of data in a message.
typedef struct CAN_DATA_BYTES_MSG
{
uint8 byte[8u];
} CAN_DATA_BYTES_MSG;
Clock Selection
The CAN component is connected to the BUS_CLK clock signal. A minimum value of 8 MHz is
required to support all standard CAN baud rates up to 1 Mbps.
Placement
The CAN component is placed in the fixed function CAN block.
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PSoC Creator™ Component Datasheet
Controller Area Network (CAN)
Resources
Digital resources
API Memory (Bytes)
Description
CAN IP Block
Interrupts
Flash
RAM
Pins (per External
I/O)
With tx_en and external interrupt
signals disabled
1*
1
4156
18
2
With tx_en signal enabled,
external interrupt signals disabled
1*
1
4156
18
3
With tx_en and external interrupt
signals enabled
1*
1
4156
18
4
*The CAN component uses the dedicated CAN hardware block in the silicon.
Application Programming Interface
Application Programming Interface (API) routines allow you to configure the component using
software. The following table lists and describes the interface to each function. The subsequent
sections cover each function in more detail.
By default, PSoC Creator assigns the instance name “CAN_1” to the first instance of a
component in a given design. You can rename the instance to any unique value that follows the
syntactic rules for identifiers. The instance name becomes the prefix of every global function
name, variable, and constant symbol. For readability, the instance name used in the following
table is “CAN.”
Function
Description
CAN_Start()
Sets the initVar variable, calls the CAN_Init() function, and then calls the
CAN_Enable() function.
CAN_Stop()
Disables the CAN.
CAN_GlobalIntEnable()
Enables global interrupts from CAN component.
CAN_GlobalIntDisable()
Disables global interrupts from CAN component.
CAN_SetPreScaler()
Sets prescaler for generation of the time quanta from the BUS_CLK.
CAN_SetArbiter()
Sets arbitration type for transmit buffers
CAN_SetTsegSample()
Configures: Time segment 1, Time segment 2, Synchronization Jump Width, and
Sampling Mode.
CAN_SetRestartType()
Sets reset type.
CAN_SetEdgeMode()
Sets Edge mode.
CAN_RXRegisterInit()
Writes only receive CAN registers.
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Controller Area Network (CAN)
Function
PSoC Creator™ Component Datasheet
Description
CAN_SetOpMode()
Sets Operation mode.
CAN_GetTXErrorflag()
Returns the flag that indicates if the number of transmit errors exceeds 0x60.
CAN_GetRXErrorflag()
Returns the flag that indicates if the number of receive errors exceeds 0x60.
CAN_GetTXErrorCount()
Returns the number of transmit errors.
CAN_GetRXErrorCount()
Returns the number of receive errors.
CAN_GetErrorState()
Returns error status of the CAN component.
CAN_SetIrqMask()
Sets to enable or disable particular interrupt sources.
CAN_ArbLostIsr()
Clears Arbitration Lost interrupt flag.
CAN_OvrLdErrrorIsr()
Clears Overload Error interrupt flag.
CAN_BitErrorIsr()
Clears Bit Error interrupt flag.
CAN_BitStuffErrorIsr()
Clears Bit Stuff Error interrupt flag.
CAN_AckErrorIsr()
Clears Acknowledge Error interrupt flag.
CAN_MsgErrorIsr()
Clears Form Error interrupt flag.
CAN_CrcErrorIsr()
Clears CRC Error interrupt flag.
CAN_BusOffIsr()
Clears Bus Off interrupt flag. Places CAN Component to Stop mode.
CAN_MsgLostIsr()
Clears Message Lost interrupt flag.
CAN_MsgTXIsr()
Clears Transmit Message interrupt flag.
CAN_MsgRXIsr()
Clears Receive Message interrupt flag and call appropriate handlers for Basic and
Full interrupt based mailboxes.
CAN_RxBufConfig()
Configures all receive registers for particular mailbox.
CAN_TxBufConfig()
Configures all transmit registers for particular mailbox.
CAN_SendMsg()
Sends an message from one of the Basic mailboxes.
CAN_SendMsg0-7()
Checks if mailbox 0-7 has untransmitted messages waiting for arbitration.
CAN_TxCancel()
Cancels transmission of a message that has been queued for transmission.
CAN_ReceiveMsg0-15()
Acknowledges receipt of new message.
CAN_ReceiveMsg()
Clears Receive particular Message interrupt flag.
CAN_Sleep()
Prepares CAN component to go to sleep
CAN_Wakeup()
Prepares CAN component to wake up
CAN_Init()
Initializes or restores the CAN per the Configure dialog settings.
CAN_Enable()
Enables the CAN.
CAN_SaveConfig()
Saves the current configuration.
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Function
Controller Area Network (CAN)
Description
CAN_RestoreConfig()
Restores the configuration.
For functions that return indication of execution, 0 is “SUCCESS,” 1 is “FAIL,” and 2 is
“OUT_OF_RANGE.”
Global Variables
Variable
CAN_initVar
Description
Indicates whether the CAN has been initialized. The variable is initialized to 0 and set to 1 the
first time CAN_Start() is called. This allows the component to restart without reinitialization after
the first call to the CAN_Start() routine.
If reinitialization of the component is required, then the CAN_Init() function can be called before
the CAN_Start() or CAN_Enable() function.
uint8 CAN_Start(void)
Description:
Sets the initVar variable, calls the CAN_Init() function, and then calls the CAN_Enable()
function. This function sets the CAN component into run mode and starts the counter if
polling mailboxes available.
Parameters:
None
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
If the initVar variable is already set, this function only calls the CAN_Enable() function.
uint8 CAN_Stop(void)
Description:
This function sets the CAN component into Stop mode and stops the counter if polling
mailboxes available.
Parameters:
None
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
None
uint8 CAN_GlobalIntEnable(void)
Description:
This function enables global interrupts from the CAN component.
Parameters:
None
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
None
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Controller Area Network (CAN)
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PSoC Creator™ Component Datasheet
uint8 CAN_GlobalIntDisable(void)
Description:
This function disables global interrupts from the CAN component.
Parameters:
None
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
None
uint8 CAN_SetPreScaler(uint16 bitrate)
Description:
This function sets the prescaler for generation of the time quanta from the BUS_CLK.
Values between 0x0 and 0x7FFF are valid.
Parameters:
uint16 bitrate: PreScaler value
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
None
uint8 CAN_SetArbiter(uint8 arbiter)
Description:
This function sets the arbitration type for transmit buffers. Types of arbiters are Round
Robin and Fixed priority. Values 0 and 1 are valid.
Parameters:
uint8 arbiter: Type of arbiter
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
None
uint8 CAN_SetTsegSample(uint8 cfgTseg1, uint8 cfgTseg2, uint8 sjw,
uint8 sm)
Description:
This function configures: Time segment 1, Time segment 2, Synchronization Jump Width,
and Sampling Mode.
Parameters:
uint8 cfgTseg1: Time segment 1, values between 0x2 and 0xF are valid
uint8 cfgTseg2: Time segment 2, values between 0x1 and 0x7 are valid
uint8 sjw: Synchronization Jump Width, values between 0x0 and 0x3 are valid.
uint8 sm: Sampling Mode, one or three sampling points are used
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
None
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Controller Area Network (CAN)
uint8 CAN_SetRestartType(uint8 reset)
Description:
This function sets reset type. Types of reset are Automatic and Manual. Manual reset is the
recommended setting. Values 0 and 1 are valid.
Parameters:
uint8 reset: Reset type
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
None
uint8 CAN_SetEdgeMode(uint8 edge)
Description:
This function sets Edge Mode. Modes are 'R' to 'D' (Recessive to Dominant) and Both
edges are used. Values 0 and 1 are valid.
Parameters:
uint8 edge: Edge Mode
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
None
uint8 CAN_RXRegisterInit(uint32 *regAddr, uint32 config)
Description:
This function writes CAN receive registers only.
Parameters:
uint32 * regAddr: Pointer to CAN receive register
uint32 configuration: Value that will be written in register
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
None
uint8 CAN_SetOpMode(uint8 opMode)
Description:
This function sets Operation Mode. Operation modes are Active or Listen Only. Values 0
and 1 are valid.
Parameters:
uint8 opMode: Operation Mode value
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
None
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PSoC Creator™ Component Datasheet
uint8 CAN_GetTXErrorflag(void)
Description:
This function returns the flag that indicates if the number of transmit errors exceeds 0x60.
Parameters:
None
Return Value:
uint8: Indication whether the number of transmit errors exceeds 0x60
Side Effects:
None
uint8 CAN_GetRXErrorflag(void)
Description:
This function returns the flag that indicates if the number of receive errors exceeds 0x60.
Parameters:
None
Return Value:
uint8: Indication whether the number of receive errors exceeds 0x60
Side Effects:
None
uint8 CAN_GetTXErrorCount(void)
Description:
This function returns the number of transmit errors.
Parameters:
None
Return Value:
uint8: Number of transmit errors
Side Effects:
None
uint8 CAN_GetRXErrorCount(void)
Description:
This function returns the number of receive errors.
Parameters:
None
Return Value:
(uint8) Number of receive errors
Side Effects:
None
uint8 CAN_GetErrorState(void)
Description:
This function returns the error status of the CAN component.
Parameters:
None
Return Value:
uint8: Error status
Side Effects:
None
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Controller Area Network (CAN)
uint8 CAN_SetIrqMask(uint16 mask)
Description:
This function enables or disables particular interrupt sources. Interrupt Mask directly writes
to the CAN Interrupt Enable register.
Parameters:
uint8 request: Interrupt enable or disable request. One bit per interrupt source
Return Value:
uint8: Indication whether register is written and verified
Side Effects:
None
void CAN_ArbLostIsr(void)
Description:
This function is the entry point to the Arbitration Lost Interrupt. It clears the Arbitration Lost
interrupt flag. It is only generated if the Arbitration Lost Interrupt parameter is enabled.
Parameters:
None
Return Value:
None
Side Effects:
None
void CAN_OvrLdErrrorIsr(void)
Description:
This function is the entry point to the Overload Error Interrupt. It clears the Overload Error
interrupt flag. It is only generated if the Overload Error Interrupt parameter is enabled.
Parameters:
None
Return Value:
None
Side Effects:
None
void CAN_BitErrorIsr(void)
Description:
This function is the entry point to the Bit Error Interrupt. It clears Bit Error interrupt flag. It is
only generated if the Bit Error Interrupt parameter is enabled.
Parameters:
None
Return Value:
None
Side Effects:
None
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PSoC Creator™ Component Datasheet
void CAN_BitStuffErrorIsr(void)
Description:
This function is the entry point to the Bit Stuff Error Interrupt. It clears the Bit Stuff Error
interrupt flag. It is only generated if the Bit Stuff Error Interrupt parameter is enabled.
Parameters:
None
Return Value:
None
Side Effects:
None
void CAN_AckErrorIsr(void)
Description:
This function is the entry point to the Acknowledge Error Interrupt. It clears the
Acknowledge Error interrupt flag. It is only generated if the Acknowledge Error Interrupt
parameter is enabled.
Parameters:
None
Return Value:
None
Side Effects:
None
void CAN_MsgErrorIsr(void)
Description:
This function is the entry point to the Form Error Interrupt. It clears the Form Error interrupt
flag. It is only generated if the Form Error Interrupt parameter is enabled.
Parameters:
None
Return Value:
None
Side Effects:
None
void CAN_CrcErrorIsr(void)
Description:
This function is the entry point to the CRC Error Interrupt. It clears the CRC Error interrupt
flag. It is only generated if the CRC Error Interrupt parameter is enabled.
Parameters:
None
Return Value:
None
Side Effects:
None
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Controller Area Network (CAN)
void CAN_BusOffIsr(void)
Description:
This function is the entry point to the Bus Off Interrupt. It puts the CAN component in Stop
mode. It is only generated if the Bus Off Interrupt parameter is enabled. Enabling this
interrupt is recommended.
Parameters:
None
Return Value:
None
Side Effects:
Stops CAN component operation
void CAN_MsgLostIsr(void)
Description:
This function is the entry point to the Message Lost Interrupt. It clears the Message Lost
interrupt flag. It is only generated if the Message Lost Interrupt parameter is enabled.
Parameters:
None
Return Value:
None
Side Effects:
None
void CAN_MsgTXIsr(void)
Description:
This function is the entry point to the Transmit Message Interrupt. It clears the Transmit
Message interrupt flag. It is only generated if the Transmit Message Interrupt parameter is
enabled.
Parameters:
None
Return Value:
None
Side Effects:
None
void CAN_MsgRXIsr(void)
Description:
This function is the entry point to the Receive Message Interrupt. It clears the Receive
Message interrupt flag and calls the appropriate handlers for Basic and Full interrupt based
mailboxes. It is only generated if the Receive Message Interrupt parameter is enabled.
Enabling this interrupt is recommended.
Parameters:
None
Return Value:
None
Side Effects:
None
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uint8 CAN_RxBufConfig(CAN_RX_CFG *rxConfig)
Description:
This function configures all receive registers for a particular mailbox. The mailbox number
contains CAN_RX_CFG structure.
Parameters:
CAN_RX_CFG * rxConfig: Pointer to structure that contains all required values to configure
all receive registers for a particular mailbox
Return Value:
uint8: Indication if particular configuration of has been accepted or rejected
Side Effects:
None
uint8 CAN_TxBufConfig(CAN_TX_CFG *txConfig)
Description:
This function configures all transmit registers for a particular mailbox. The mailbox number
contains CAN_TX_CFG structure.
Parameters:
CAN_TX_CFG * txConfig: Pointer to structure that contains all required values to configure
all transmit registers for a particular mailbox
Return Value:
uint8: Indication if particular configuration of has been accepted or rejected
Side Effects:
None
uint8 CAN_SendMsg(CANTXMsg *message)
Description:
This function sends a message from one of the Basic mailboxes. The function loops through
the transmit message buffer designed as Basic CAN mailboxes. It looks for the first free
available mailbox and sends from it. There can only be three retries.
Parameters:
CAN_TX_MSG * message: Pointer to structure containing required data to send message
Return Value:
uint8: Indication if message has been sent
Side Effects:
None
uint8 CAN_SendMsg0-7(void)
Description:
These functions are the entry point to Transmit Message 0-7. This function checks if
mailbox 0-7 already has untransmitted messages waiting for arbitration. If so, it initiates
transmission of the message. Only generated for Transmit mailboxes designed as Full.
Parameters:
None
Return Value:
uint8: Indication if Message has been sent
Side Effects:
None
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Controller Area Network (CAN)
void CAN_TxCancel(uint8 bufferld)
Description:
This function cancels transmission of a message that has been queued for transmission.
Values between 0 and 15 are valid.
Parameters:
uint8 bufferld: Number of Tx mailbox.
Return Value:
None
Side Effects:
None
void CAN_ReceiveMsg0-15(void)
Description:
These functions are the entry point to the Receive Message 0-15 Interrupt. They clear
Receive Message 0 - 15 interrupt flags. They are only generated for Receive mailboxes
designed as Full interrupt based.
Parameters:
None
Return Value:
None
Side Effects:
None
void CAN_ReceiveMsg(uint8 rxMailbox)
Description:
This function is the entry point to the Receive Message Interrupt for Basic mailboxes. It
clears the Receive particular Message interrupt flag. It is only generated if one of the
Receive mailboxes is designed as Basic.
Parameters:
uint8 rxMailbox: Mailbox number that triggers Receive Message Interrupt
Return Value:
None
Side Effects:
None
void CAN_Sleep(void)
Description:
This is the preferred routine to prepare the component for sleep. The CAN_Sleep() routine
saves the current component state. Then it calls the CAN_Stop() function and calls
CAN_SaveConfig() to save the hardware configuration.
Call the CAN_Sleep() function before calling the CyPmSleep() or the CyPmHibernate()
function. Refer to the PSoC Creator System Reference Guide for more information about
power management functions.
Parameters:
None
Return Value:
None
Side Effects:
None
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void CAN_Wakeup(void)
Description:
This is the preferred routine to restore the component to the state when CAN_Sleep() was
called. The CAN_Wakeup() function calls the CAN_RestoreConfig() function to restore the
configuration. If the component was enabled before the CAN_Sleep() function was called,
the CAN_Wakeup() function will also re-enable the component.
Parameters:
None
Return Value:
None
Side Effects:
Calling the CAN_Wakeup() function without first calling the CAN_Sleep() or
CAN_SaveConfig() function may produce unexpected behavior.
uint8 CAN_Init(void)
Description:
Initializes or restores the component according to the customizer Configure dialog settings.
It is not necessary to call CAN_Init() because the CAN_Start() routine calls this function and
is the preferred method to begin component operation.
Parameters:
None
Return Value:
uint8: Indication whether the configuration has been accepted or rejected
Side Effects:
All registers will be reset to their initial values. This reinitializes the component with the
following exception: it will not clear data from the mailboxes.
Enables power to the CAN Core.
uint8 CAN_Enable(void)
Description:
Activates the hardware and begins component operation. It is not necessary to call
CAN_Enable() because the CAN_Start() routine calls this function, which is the preferred
method to begin component operation.
Parameters:
None
Return Value:
None
Side Effects:
None
void CAN_SaveConfig(void)
Description:
This function saves the component configuration and nonretention registers. This function
also saves the current component parameter values, as defined in the Configure dialog or as
modified by appropriate APIs. This function is called by the CAN_Sleep() function.
Parameters:
None
Return Value:
None
Side Effects:
None
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Controller Area Network (CAN)
void CAN_RestoreConfig(void)
Description:
This function restores the component configuration and nonretention registers. This function
also restores the component parameter values to what they were prior to calling the
CAN_Sleep() function.
Parameters:
None
Return Value:
None
Side Effects:
Calling this function without first calling the CAN_Sleep() or CAN_SaveConfig() function may
produce unexpected behavior. The following registers will revert to default values:
CAN_INT_SR, CAN_INT_EN, CAN_CMD, and CAN_CFG.
Sample Firmware Source Code
PSoC Creator provides many example projects that include schematics and example code in the
Find Example Project dialog. For component-specific examples, open the dialog from the
Component Catalog or an instance of the component in a schematic. For general examples,
open the dialog from the Start Page or File menu. As needed, use the Filter Options in the
dialog to narrow the list of projects available to select.
Refer to the “Find Example Project” topic in the PSoC Creator Help for more information.
Interrupt Service Routines
There are several CAN component interrupt sources:











Arbitration Lost Detection – The arbitration was lost while sending a message
Overload Error – An overload frame was received
Bit Error – A bit error was detected
Bit Stuff Error - A bit stuffing error was detected
Acknowledge Error – CAN message acknowledge error was detected
Form Error – CAN message format error was detected
CRC Error – CAN CRC error was detected
Bus Off – CAN has reached the bus off state
Message Lost – A new message arrived but there was nowhere to put it
Transmit Message – The queued message was sent
Receive Message – A message was received
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All of these interrupt sources have entry points (functions) so you can place code in them. These
functions are conditionally compiled depending on the customizer.
The Receive Message interrupt has a special handler that calls appropriate functions for Full and
Basic mailboxes.
Interrupt Output Use Cases
The following are example use cases of the hardware interrupt output line in the CAN
component:
Hardware Control of Logic on Interrupt Events
The hardware interrupt line can be used to perform simple tasks such as estimating the CAN bus
load. By enabling the Message Transmitted and Message Received interrupts in the CAN
component customizer, and connecting the interrupt line to a counter, the number of messages
that are on the bus during a specific time interval can be evaluated. Also, actions can be taken
directly in hardware if the message rate is above a certain value.
Interrupt Output Interaction with DMA
The CAN component doesn't support DMA operation internally, but you can connect the DMA
component to the external interrupt line (if it is enabled). You are responsible for the DMA
configuration and operation. Also, you should keep in mind that it is necessary to handle some
housekeeping tasks (for example, acknowledging the message and clearing the interrupt flags)
in code for proper handling of CAN interrupts.
With a hardware DMA trigger you can handle registers and data transfers when a Message
Received interrupt occurs, without any firmware executing in the CPU. This is also useful when
handling RTR messages. The Message Transmitted interrupt can be used to trigger a DMA
transfer to reload the message buffer with new data, without CPU intervention.
Custom External Interrupt Service Routine
Custom external ISRs can be used in addition to or as a replacement to the internal ISR. When
the external ISR is used in addition to the internal ISR, the Interrupt priority can be set to
determine which ISR should execute first (internal or external), thus forcing actions before or
after those coded in the internal ISR. When the external ISR is used as replacement for the
internal ISR, you assume all responsibility for proper handling of CAN registers and events.
Interrupt Output Interaction with the Interrupt Subsystem
The CAN component Interrupt Output settings allow you to:


Enable or disable an external interrupt line (customizer option)
Disable or bypass the internal ISR (customizer option)
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

Controller Area Network (CAN)
Fully customize the internal ISR (customizer option)
Enable or disable specific interrupts handling function calls in the internal ISR, when the
relevant event interrupts are enabled (customizer option). Individual interrupts (message
transmitted, message received, receive buffer full, bus off state, and so on) can be enabled or
disabled in the CAN component customizer. Once enabled the relevant function call is
executed in the internal CAN_ISR. This allows you to disable (remove) such function calls.
The external interrupt line is visible only if enabled in the customizer.
If an external Interrupt component is connected, then the external Interrupt component is not
started as part of the CAN_Start() API, and will have to be started outside that routine.
If an external Interrupt component is connected and the internal ISR is not disabled or bypassed,
then two Interrupt components are connected to the same line. And in this case you will have
two separate Interrupt components that will handle the same interrupt events. This is a specific,
and in most cases undesirable, situation.
If the internal ISR is disabled or bypassed (using a customizer option) the internal Interrupt
component will be removed during the build process.
If you choose to disable an individual interrupt function call in the internal interrupt routine (for an
enabled interrupt event, by using a customizer option), the CAN block interrupt triggers (when
the relevant event occurs), but no internal function call is executed in the internal CAN_ISR
routine. An example use case is when you want to handle a specific event (for example,
message received) through a different path, other than the standard user function call (for
example, through DMA).
If you choose to fully customize the internal ISR (via customizer option) the CAN_ISR function
will not contain any function call other than the optional PSoC3 ES1/ES2 ISR patch.
Functional Description
For a complete description, refer to the Controller Area Network (CAN) chapter in the PSoC® 3
and PSoC® 5 Technical Reference Manual.
Block Diagram and Configuration
For complete block diagram and configuration information, refer to the Controller Area Network
(CAN) chapter in the PSoC® 3 and PSoC® 5 Technical Reference Manual.
References
1. ISO-11898: Road vehicles -- Controller area network (CAN):
 Part 1: Data link layer and physical signaling
 Part 2: High-speed medium access unit
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Controller Area Network (CAN)
PSoC Creator™ Component Datasheet
 Part 3: Low-speed, fault-tolerant, medium-dependent interface
 Part 4: Time-triggered communication
 Part 5: High-speed medium access unit with low-power mode
2. CAN Specification Version 2 BOSCH
3. Inicore CANmodule-III-AHB Datasheet
DC and AC Electrical Characteristics
The following values indicate expected performance and are based on initial characterization
data.
CAN DC Specifications
Parameter
Description
Block current consumption
Conditions
Min
Typ
Max
Units
500 kbps
--
--
285
A
1 Mbps
--
--
330
A
Min
Typ
Max
--
--
1
CAN AC Specifications
Parameter
Description
Bit rate
Conditions
Minimum 8 MHz clock
Units
Mbit
Component Changes
This section lists the major changes in the component from the previous version.
Current
Version
2.0.a
Description of Changes
Reason for Changes / Impact
Replaced timing diagram and added
descriptive text to datasheet
Minor datasheet edits and updates
2.0
Added interrupt output to the
component symbol
Updated Marketing Requirements Document MRD for the
PSoC3 CAN Component
Updated Marketing Requirements Document MRD for the
Added ConnectExtInterruptLine,
PSoC3 CAN Component
IntISRDisable, FullCastomIntISR,
AdvancedInterruptTab parameters and
ISR helper parameters in the
component symbol
Added stop statement at the beginning To ensure that CAN is stopped at initialization
of the CAN_Init() function.
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PSoC Creator™ Component Datasheet
Current
Version
Description of Changes
Controller Area Network (CAN)
Reason for Changes / Impact
Updated interrupt handlers functions.
To clear interrupt flags in the same manner
In all cases the interrupt flag is cleared
before the user code.
Removed obsolete defines
1.50.a
Added characterization data to
datasheet
Datasheet text edits
1.50
Added Sleep / Wakeup APIs.
These APIs provide support for low-power modes.
Added CAN_Init() and CAN_Enable()
APIs.
To comply with corporate standard and provide an API to
initialize/restore the component without starting it.
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Document Number: 001-71391 Rev. *A
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