M16C1N Datasheet, PDF (164/238 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/10 SERIES

M16C/1N Group
16. CAN Module
16.12.1 Reception
Figure 16.24 shows the behavior of the module when receiving two consecutive CAN messages.
SOF
CANbus
RecReq
InvalData
NewData
MsgLost
Succ.Rec Int.
RecState
(1)
RecSucc
MBOX
ACK
EOF
IFS SOF
ACK
EOF
IFS
(2)
(2)
(4)
(3)
(5)
(5)
(5)
Receive slot No.
Figure 16.24 Timing of Receive Data Frame Sequence
(1) On monitoring a SOF on the bus the RecState bit becomes active immediately, given the module
has no transmission pending (see section "16.12.2 Transmission" below).
(2) After successful reception of the message the NewData bit of the receiving slot becomes active.
The InvalData bit becomes active at the same time and becomes inactive again after the complete
message was transferred to the slot.
(3) When the bit in the C0ICR register of the receiving slot is active the receive successful interrupt is
requested and the C0STR register changes. It shows the slot number where the message was
stored and the RecSucc bit is active.
(4) Read the message out of the slot after setting the New Data bit to “0” by a program.
(5) If the NewData bit is set to "0" by a program or the next CAN message is received successfully
before the reception request for the slot is canceled, the MsgLost bit is set to "1". The new received
message is transferred to the slot. The interrupt request and the C0STR register change like (3).
Rev.1.00 Oct 20, 2004 page 152 of 222
REJ09B0007-0100Z