SWRU626 December 2025 CC3501E , CC3551E
The Tx Buffers section can be configured to hold dedicated Tx Buffers as well as a Tx FIFO / Tx Queue. In case that the Tx Buffers section is shared by dedicated Tx buffers and a Tx FIFO / Tx Queue, the dedicated Tx Buffers start at the beginning of the Tx Buffers section followed by the buffers assigned to the Tx FIFO or Tx Queue. The Tx Handler distinguishes between dedicated Tx Buffers and Tx FIFO / Tx Queue by evaluating the Tx Buffer configuration TXBC.TFQS and TXBC.NDTB.
| Tx Buffer | Bit | Name | Description |
|---|---|---|---|
| T0 | 30 | XTD |
Extended Identifier 0= 11-bit standard identifier 1= 29-bit extended identifier |
| 29 | RTR |
Remote Transmission Request 0= Transmit data frame 1= Transmit remote frame Note: WhenRTR = 1, the DCAN transmits a remote frame according to ISO 11898-1:2015 |
|
| 28:0 | ID[28:0] |
Identifier Standard or extended identifier depending on bit XTD. A standard identifier has to be written to ID[28:18]. |
|
| T1 | 31:24 | MM[7:0] |
Message Marker Written by CPU during Tx Buffer configuration. Copied into Tx Event FIFO element for identification of Tx message status. |
| 23 | EFC |
Event FIFO Control 0= Don’t store Tx events 1= Store Tx events |
|
| 18:16 | DLC[2:0] |
Data Length Code 0-8= CAN transmit frame has 0-8 data bytes |
|
| T2 | 31:24 | DB3[7:0] | Data Byte 3 |
| 23:16 | DB2[7:0] | Data Byte 2 | |
| 15:8 | DB1[7:0] | Data Byte 1 | |
| 7:0 | DB0[7:0] | Data Byte 0 | |
| T3 | 31:24 | DB7[7:0] | Data Byte 7 |
| 23:16 | DB6[7:0] | Data Byte 6 | |
| 15:8 | DB5[7:0] | Data Byte 5 | |
| 7:0 | DB4[7:0] | Data Byte 4 |
Depending on the configuration of the element size (TXESC), between two and sixteen 32-bit words (Tn = 3 ..17) are used for storage of a CAN message’s data field.