Controller Area Network (FlexCAN)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
25-22
Freescale Semiconductor
Preliminary
25.3.4.6
Error and Status Register (CANx_ESR)
This register reflects various error conditions, some general status of the device, and it is the source of four
interrupts to the CPU. The reported error conditions (bits 16-21) are those that occurred since the last time
the CPU read this register. The CPU read action clears bits 16-21. Bits 22-28 are status bits.
Most bits in this register are read only, except TWRN_INT, RWRN_INT, BOFF_INT, and ERR_INT,
which are interrupt flags that can be cleared by writing 1 to them (writing 0 has no effect).
NOTE
A read clears BIT1ERR, BIT0ERR, ACKERR, CRCERR, FRMERR, and
STFERR, therefore these bits must not be read speculatively.
Offset: Base + 0x001C
Access: User read/write
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
0
0
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
Rx_Err_Counter
Tx_Err_Counter
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 25-9. Error Counter Register (CANx_ECR)
Offset: Base + 0x0020
Access: User read/write
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_
WRN
RX_
WRN
IDLE TXRX FLT_CONF
0
BOFF_
INT
ERR_
INT
0
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 25-10. Error and Status Register (CANx_ESR)