SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
Up to 64 Rx Buffers and two Rx FIFOs can be configured in the Message RAM. Each Rx FIFO section can be configured to store up to 64 received messages. The element size can be configured for storage of CAN FD messages with up to 64 bytes data field via the MCAN_RXESC register.
Figure 12-2746 shows Rx Buffer/Rx FIFO element structure.
Table 12-5209 shows Rx Buffer/Rx FIFO element field descriptions.
Word | Bits | Field Name | Description | ||
---|---|---|---|---|---|
R0 | 31 | ESI | Error State Indicator
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30 | XTD | Extended Identifier Signals to the Host CPU whether the received frame has a standard or extended identifier.
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29 | RTR | Remote Transmission Request Signals to the Host CPU whether the received frame is a data frame or a remote frame.
Note: There are no remote frames in CAN FD format. In case a CAN FD frame was received (FDF = 1), RTR bit reflects the state of the reserved r1 bit (RES[23]). | |||
28-0 | ID[28-0] | Identifier Standard or extended identifier depending on XTD bit. A standard identifier is stored into ID[28-18]. | |||
R1 | 31 | ANMF | Accepted Non-matching Frame Acceptance of non-matching frames may be enabled via the MCAN_GFC[5-4] ANFS and MCAN_GFC[3-2] ANFE fields.
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30-24 | FIDX[6-0] | Filter Index 0h-7Fh (0-127): Index of matching Rx acceptance filter element (invalid if ANMF = 1). Range is 0 to MCAN_SIDFC[23-16] LSS - 1 respectively MCAN_XIDFC[22-16] LSE - 1. | |||
23-22 | RES | Reserved | |||
21 | FDF | FD Format
| |||
20 | BRS | Bit Rate Switch
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19-16 | DLC[3-0] | Data Length Code
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15-0 | RXTS[15-0] | Rx Timestamp Timestamp Counter value captured on start of frame reception. Resolution depending on configuration of the Timestamp Counter Prescaler MCAN_TSCC[19-16] TCP. | |||
R2 | 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 | |||
R3 | 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 | |||
... | ... | ... | ... | ||
Rn | 31-24 | DBm[7-0] | Data Byte m | ||
23-16 | DBm-1[7-0] | Data Byte m-1 | |||
15-8 | DBm-2[7-0] | Data Byte m-2 | |||
7-0 | DBm-3[7-0] | Data Byte m-3 |
Note: Depending on the configuration of the element size (MCAN_RXESC), between two and sixteen 32-bit words (Rn = 3-17) are used for storage of a CAN message's data field.