Renesas M32R/ECU Series User Manual page 630

13
(2) When the receive conditions are met
When the receive conditions in (1) above are met, the CAN module sets the CAN Message Slot Control
Register's TRSTAT (Transmit/Receive Status) bit and TRFIN (Transmit/Receive Finished) bit to "1" while at
the same time writing the received data to the message slot. If the TRFIN (Transmit/Receive Finished) bit is
already set to "1" at this time, the CAN module also sets the ML (Message Lost) bit to "1", indicating that the
message slot has been overwritten. The message slot has both of its ID and DLC fields entirely overwritten
and has an undefined value written in its unused area (e.g., extended ID field during standard frame recep-
tion and an unused data field).
Furthermore, a timestamp count value at which the message was received is written to the CAN Message
Slot Timestamp (C0MSLnTSP, C1MSLnTSP) along with the received data. When the CAN module finished
writing to the message slot, it sets the CAN Slot Interrupt Request Status bit to "1". If the interrupt request for
the slot has been enabled, the CAN module generates an interrupt request and enters a wait state for the
next reception.
(3) When the receive conditions are not met
The received frame is discarded, and the CAN module goes to the next transmit/receive operation without
writing to the message slot.
Bit arrangement in the CAN Message Slot Control Register
b0 (b8) 1 2 3
TR RR RM RL
0 0 0 0
Finished storing
the received data
Finished storing
the received data
Figure 13.6.2 Operation of the CAN Message Slot Control Register during Data Frame Reception
4 5 6 b7(b15)
RA ML TRSTAT TRFIN
0 0 0 0
Clear the receive
request
B'0000 0011
Clear the receive
B'0000 0001
Clear the receive
B'0000 0111
B'0000 0101
Clear the receive
B'0000 0000
Set a receive
Clear the receive request
request
B'0100 0000
Store the received data
B'0100 0011
Finished storing the received data
request
B'0100 0001
Store the received data
request
B'0100 0111
Finished storing
Store the received data
the received
data
B'0100 0101
request
13-83
CAN MODULE
13.6 Receiving Data Frames
Wait for the received data
Wait for the
received data
32180 Group User's Manual (Rev.1.0)