Can 0 i, Nterrupt, Egister – Maxim Integrated High-Speed Microcontroller Users Guide: DS80C390 Supplement User Manual
Page 42: C0ir)
High-Speed Microcontroller User’s Guide: DS80C390 Supplement
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arbitration field (identifier and remote retransmission request).
Bit 0 Error
: Indicates that the CAN attempted to transmit a message and that
when a dominant bit was transmitted, the CAN bus was found to have a
recessive bit level. This error is not generated when the bit is a part of the
arbitration field. The Bit 0 Error is set each time a recessive bit is received
during the Busoff recovery period.
CRC Error
: Generated whenever the calculated CRC of a received message does
not match the CRC embedded in the message.
CAN 0 INTERRUPT REGISTER (C0IR)
7 6 5 4 3 2 1 0
SFR A5h
R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0
R = Unrestricted Read, W = Unrestricted Write, -n = Value after Reset
C0IR.7-0
Bit 7-5
CAN 0 Interrupt Indicator 7-0 This register indicates the status of the
interrupt source associated with the CAN 0 module. Reading this register
after the generation of a CAN 0 Interrupt will identify the interrupt source as
shown in the table below. This register is cleared to 00h following a reset.
C0IR.7-0 Priority
Interrupt
Source
00h
N/A
No Pending Interrupt
01h
1 (highest)
Change in the CAN 0 Status Register
02h 2
Message
15
03h 3
Message
1
04h 4
Message
2
05h 5
Message
3
06h 6
Message
4
07h 7
Message
5
08h 8
Message
6
09h 9
Message
7
0Ah 10
Message
8
0Bh 11
Message
9
0Ch 12
Message
10
0Dh 13
Message
11
0Eh 14
Message
12
0Fh 15
Message
13
10h
16 (lowest)
Message 14
The C0IR value will not change unless the previous interrupt source has been
acknowledged and removed (i.e., software read of the C0S register or clearing of
the appropriate INTRQ bit), even if the new interrupt has a higher priority. If two
enabled interrupt sources become active simultaneously, the interrupt of higher
priority will be reflected in the C0IR value.
The CAN 0 interrupt source into the interrupt logic is active whenever C0IR is not
equal to 00h. Changes in the C0IR value from 00h to a non-zero state, indicate the