MPC555
/
MPC556
CAN 2.0B CONTROLLER MODULE
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
16-35
16.7.14 Interrupt Flag Register
16.7.15 Error Counters
IFLAG —
Interrupt Flag Register
0x30 70A4
0x30 74A4
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LSB
15
IFLAGH
IFLAGL
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 16-25 IFLAG Bit Descriptions
Bit(s)
Name
Description
0:7,
8:15
IFLAGH,
IFLAGL
IFLAG contains two 8-bit fields, IFLAGH and IFLAGL. IFLAG can be accessed with a 16-bit
read or write, and IFLAGH and IFLAGL can be accessed with byte reads or writes.
IFLAG contains one interrupt flag bit per buffer. Each successful transmission/reception sets
the corresponding IFLAG bit and, if the corresponding IMASK bit is set, an interrupt request
will be generated.
To clear an interrupt flag, first read the flag as a one, and then write it as a zero. Should a
new flag setting event occur between the time that the CPU reads the flag as a one and
writes the flag as a zero, the flag is not cleared. This register can be written to zeros only.
NOTE
: Bit 15 (LSB) corresponds to message buffer 0. Bit 0 (MSB) corresponds to mesage
buffer 15.
RXECTR —
Receive Error Counter
0x30 70A6, 0x30 74A6
TXECTR —
Transmit Error Counter
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LSB
15
RXECTR
TXECTR
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 16-26 RXECTR, TXECTR Bit Descriptions
Bit(s)
Name
Description
0:7,
8:15
RXECTR,
TXECTR
Both counters are read only, except when the TouCAN is in test or debug mode.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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