
2010 Microchip Technology Inc.
DS21801F-page 67
MCP2515
FIGURE 12-8:
READ STATUS INSTRUCTION
FIGURE 12-9:
RX STATUS INSTRUCTION
SO
SI
SCK
CS
0
23456789
10 11
12 13 14 15 16 17 18 19 20 21 22
1
00
0
1
0
10
76543210
instruction
data out
high-impedance
23
don’t care
CANINTF.RX0IF
CANINTFL.RX1IF
CANINTF.TX0IF
CANINTF.TX1IF
CANINTF.TX2IF
TXB2CNTRL.TXREQ
TXB1CNTRL.TXREQ
TXB0CNTRL.TXREQ
765
43210
data out
repeat
SO
SI
SCK
CS
0
23456789
10 11
12 13 14 15 16 17 18 19 20 21 22
1
00
0
1
0
10
76543210
instruction
data out
high-impedance
23
don’t care
76
543210
data out
repeat
2
1 0
Filter Match
00
0
RXF0
00
1
RXF1
01
0
RXF2
01
1
RXF3
10
0
RXF4
10
1
RXF5
11
0
RXF0 (rollover to RXB1)
11
1
RXF1 (rollover to RXB1)
CANINTF.RXnIF bits are mapped to
bits 7 and 6.
7
6
Received Message
00
No RX message
01
Message in RXB0
10
Message in RXB1
11
Messages in both buffers*
The extended ID bit is mapped to
bit 4. The RTR bit is mapped to
bit 3.
4
3
Msg Type Received
00
Standard data frame
01
Standard remote frame
10
Extended data frame
11
Extended remote frame
* Buffer 0 has higher priority, therefore, RXB0 status is
reflected in bits 4:0.