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MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
1291
Preliminary—Subject to Change Without Notice
Most bits in this register are read only, except TWRN_INT, RWRN_INT, BOFF_INT, WAK_INT and
ERR_INT, that are interrupt flags that can be cleared by writing ‘1’ to them (writing ‘0’ has no effect). See
Section 28.5.10, “Interrupts,”
for more details.
Figure 28-10. Error and Status Register (ESR)
TWRN_INT — Tx Warning Interrupt Flag
If the WRN_EN bit in MCR is asserted, the TWRN_INT bit is set when the TX_WRN flag transition
from ‘0’ to ‘1’, meaning that the Tx error counter reached 96. If the corresponding mask bit in the
Control Register (TWRN_MSK) is set, an interrupt is generated to the CPU. This bit is cleared by
writing it to ‘1’. Writing ‘0’ has no effect.
1 = The Tx error counter transition from < 96 to
≥
96
0 = No such occurrence
RWRN_INT — Rx Warning Interrupt Flag
If the WRN_EN bit in MCR is asserted, the RWRN_INT bit is set when the RX_WRN flag transition
from ‘0’ to ‘1’, meaning that the Rx error counters reached 96. If the corresponding mask bit in the
Control Register (RWRN_MSK) is set, an interrupt is generated to the CPU. This bit is cleared by
writing it to ‘1’. Writing ‘0’ has no effect.
1 = The Rx error counter transition from < 96 to
≥
96
0 = No such occurrence
BIT1_ERR — Bit1 Error
This bit indicates when an inconsistency occurs between the transmitted and the received bit in a
message.
1 = At least one bit sent as recessive is received as dominant
0 = No such occurrence
NOTE
This bit is not set by a transmitter in case of arbitration field or ACK slot, or
in case of a node sending a passive error flag that detects dominant bits.
Base + $0020
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R
0
0
0
0
0
0
0
0
0
0
0
0
0
0
TWRN
_INT
RWRN
_INT
W
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R
BIT1_
ERR
BIT0_
ERR
ACK_
ERR
CRC_
ERR
FRM_
ERR
STF_
ERR
TX_W
RN
RX_
WRN
IDLE TXRX
FLT_CONF
0
BOFF
_INT
ERR_
INT
WAK_
INT
W
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved