14.4.1 CAN FD x Control Register
Note:
- These bits can only be
modified in Configuration mode (OPMOD[2:0] =
100).
| Name: | CxCON |
| Offset: | 0x2600, 0x28F0 |
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| TXBWS[3:0] | ABAT | REQOP[2:0] | |||||||
| Access | R/W | R/W | R/W | R/W | S/HC | R/W | R/W | R/W | |
| Reset | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | |
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| OPMOD[2:0] | TXQEN | STEF | SERR2LOM | ESIGM | RTXAT | ||||
| Access | R | R | R | R/W | R/W | R/W | R/W | R/W | |
| Reset | 1 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | |
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| ON | SIDL | BRSDIS | BUSY | WFT[1:0] | WAKFIL | ||||
| Access | R/W | R/W | R/W | R | R/W | R/W | R/W | ||
| Reset | 0 | 0 | 0 | 0 | 1 | 1 | 1 | ||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| CLKSEL | PXEDIS | ISOCRCEN | DNCNT[4:0] | ||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W | |
| Reset | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | |
Bits 31:28 – TXBWS[3:0] Transmit Bandwidth Sharing bits
| Value | Description |
|---|---|
| 1111-1100 | 4096 |
| 1011 | 2048 |
| 1010 | 1024 |
| 1001 | 512 |
| 1000 | 256 |
| 0111 | 128 |
| 0110 | 64 |
| 0101 | 32 |
| 0100 | 16 |
| 0011 | 8 |
| 0010 | 4 |
| 0001 | 2 |
| 0000 | No delay |
Bit 27 – ABAT Abort All Pending Transmissions bit
| Value | Description |
|---|---|
| 1 | Signals all transmit buffers to abort transmission. |
| 0 | Module will clear this bit when all transmissions are aborted. |
Bits 26:24 – REQOP[2:0] Request Operation Mode bits
| Value | Description |
|---|---|
| 111 | Sets Restricted Operation mode. |
| 110 | Sets Normal CAN 2.0 mode; error frames on CAN FD frames. |
| 101 | Sets External Loopback mode. |
| 100 | Sets Configuration mode. |
| 011 | Sets Listen Only mode. |
| 010 | Sets Internal Loopback mode. |
| 001 | Sets Disable mode. |
| 000 | Sets Normal CAN FD mode; supports mixing of full CAN FD and Classic CAN 2.0 frames. |
Bits 23:21 – OPMOD[2:0] Operation Mode Status bits
| Value | Description |
|---|---|
| 111 | Module is in Restricted Operation mode. |
| 110 | Module is in Normal CAN 2.0 mode; error frames on CAN FD frames. |
| 101 | Module is in External Loopback mode. |
| 100 | Module is in Configuration mode. |
| 011 | Module is in Listen Only mode. |
| 010 | Module is in Internal Loopback . |
| 001 | Module is in Disable mode. |
| 000 | Module is in Normal CAN FD mode; supports mixing of full CAN FD and Classic CAN 2.0 frames. |
Bit 20 – TXQEN Enable Transmit Queue bit(1)
| Value | Description |
|---|---|
| 1 | Enables TXQ and reserves space in RAM. |
| 0 | Does not reserve space in RAM for TXQ. |
Bit 19 – STEF Store in Transmit Event FIFO bit(1)
| Value | Description |
|---|---|
| 1 | Saves transmitted messages in TEF. |
| 0 | Does not save transmitted messages in TEF. |
Bit 18 – SERR2LOM Transition to Listen Only Mode on System Error bit(1)
| Value | Description |
|---|---|
| 1 | Transitions to Listen Only mode on System Error. |
| 0 | Transitions to Restricted Operation mode on System Error. |
Bit 17 – ESIGM Transmit ESI in Gateway Mode bit(1)
| Value | Description |
|---|---|
| 1 | ESI is transmitted as recessive when the ESI of message is high or CAN controller is error passive. |
| 0 | ESI reflects error status of the CAN controller. |
Bit 16 – RTXAT Restrict Retransmission Attempts bit(1)
| Value | Description |
|---|---|
| 1 | Restricted retransmissions attempts, uses TXAT[1:0]. |
| 0 | Unlimited number of retransmission attempts, TXAT[1:0] bits will be ignored. |
Bit 15 – ON CAN Enable bit
| Value | Description |
|---|---|
| 1 | CAN module is enabled. |
| 0 | CAN module is disabled. |
Bit 13 – SIDL CAN stop in Idle Mode bit
| Value | Description |
|---|---|
| 1 | Stops module operation in Idle mode. |
| 0 | Does not stop module operation in Idle mode. |
Bit 12 – BRSDIS Bit Rate Switching (BRS) Disable bit
| Value | Description |
|---|---|
| 1 | Bit rate switching is disabled, regardless of BRS in the transmit message object. |
| 0 | Bit rate switching depends on the BRS of the transmit message object. |
Bit 11 – BUSY CAN Module is Busy bit
| Value | Description |
|---|---|
| 1 | The CAN module is active. |
| 0 | The CAN module is inactive. |
Bits 10:9 – WFT[1:0] Selectable Wake-up Filter Time bits
| Value | Description |
|---|---|
| 11 | T11 Filter |
| 10 | T10 Filter |
| 01 | T01 Filter |
| 00 | T00 Filter |
Bit 8 – WAKFIL Enable CAN Bus Line Wake-up Filter bit(1)
| Value | Description |
|---|---|
| 1 | Uses CAN bus line filter for wake-up. |
| 0 | CAN bus line filter is not used for wake-up. |
Bit 7 – CLKSEL CAN Module Clock Source Select bit(1)
| Value | Description |
|---|---|
| 1 | CAN module runs at system (CPU) clock. |
| 0 | CAN module clock is derived from Clock Generator 10. |
Bit 6 – PXEDIS Protocol Exception Event Detection Disabled bit(1)
| Value | Description |
|---|---|
| 1 | Protocol exception is treated as a form error. |
| 0 | If a protocol exception is detected, CAN will enter the Bus Integrating state. |
Bit 5 – ISOCRCEN Enable ISO CRC in CAN FD Frames bit(1)
| Value | Description |
|---|---|
| 1 | Includes stuff bit count in CRC field and uses nonzero CRC initialization vector. |
| 0 | Does not include stuff bit count in CRC field and uses CRC initialization vector with all zeroes. |
Bits 4:0 – DNCNT[4:0] DeviceNet™ Filter Bit Number bits
| Value | Description |
|---|---|
| 11111-10011 | Invalid selection (compares up to 18 bits of data with EIDx) |
| 10010 | Compares up to Data Byte 2, bit 6 with EID17. |
| 10001 | Compares up to Data byte 2, bit 7 with EID16. |
| ... | ... |
| 00010 | Compares up to Data byte 0 bit 6 with EID1. |
| 00001 | Compares up to Data byte 0 bit 7 with EID0. |
| 00000 | Does not compare data bytes. |