RM0090 Rev 18 1091/1749
RM0090 Controller area network (bxCAN)
1121
32.7.5 Message storage
The interface between the software and the hardware for the CAN messages is
implemented by means of mailboxes. A mailbox contains all information related to a
message; identifier, data, control, status and time stamp information.
Transmit mailbox
The software sets up the message to be transmitted in an empty transmit mailbox. The
status of the transmission is indicated by hardware in the CAN_TSR register.
Receive mailbox
When a message has been received, it is available to the software in the FIFO output
mailbox. Once the software has handled the message (e.g. read it) the software must
release the FIFO output mailbox by means of the RFOM bit in the CAN_RFR register to
make the next incoming message available. The filter match index is stored in the MFMI
field of the CAN_RDTxR register. The 16-bit time stamp value is stored in the TIME[15:0]
field of CAN_RDTxR.
Table 182. Transmit mailbox mapping
Offset to transmit mailbox base address (bytes) Register name
0CAN_TIxR
4 CAN_TDTxR
8CAN_TDLxR
12 CAN_TDHxR
Table 183. Receive mailbox mapping
Offset to receive mailbox base address (bytes) Register name
0CAN_RIxR
4 CAN_RDTxR
8 CAN_RDLxR
12 CAN_RDHxR
To Next Page
Loading...
Need help?
General
