MC68HC05X16 Datasheet, PDF (72/232 Pages) Freescale Semiconductor, Inc – High-density complementary metal oxide semiconductor HCMOS) microcontroller unit

Freescale Semiconductor, Inc.
5.3.3 MCAN status register (CSTAT)
This is a read only register; only the MCAN can change its contents.
Address bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Reset condition
State
on reset
MCAN status
External reset 0000 1100
(CSTAT)
$0022 BS ES TS RS TCS TBA DO RBS
RR bit set uu00 1100
BS — Bus status
5
This bit is set (off-bus) by the MCAN when the transmit error counter reaches 256. The MCAN will
then set RR and will remain off-bus until the CPU clears RR again. At this point the MCAN will wait
for 128 successive occurrences of a sequence of 11 recessive bits before clearing BS and
resetting the read and write error counters. While off-bus the MCAN does not take part in bus
activities.
1 (set) – Off-bus – The MCAN is not participating in bus activities.
0 (clear) – On-bus – The MCAN is operating normally.
ES — Error status
1 (set) – Error – Either the read or the write error counter has reached the
CPU warning limit of 96.
0 (clear) – Neither of the error counters has reached 96.
TS — Transmit status
1 (set) – Transmit – The MCAN has started to transmit a message.
0 (clear) – Idle – If the receive status bit is also clear then the MCAN is idle;
otherwise it is in receive mode.
RS — Receive status
1 (set) – Receive – The MCAN entered receive mode from idle, or by losing
arbitration during transmission.
0 (clear) – Idle – If the transmit status bit is also clear then the MCAN is idle;
otherwise it is in transmit mode.
MOTOROLA CAN MODULE (MCAN)
MC68HC05X16
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Rev. 1
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