Technical data

MOTOROLA MC68HC912B32
126 MC68HC912B32TS/D
These bits are used to compare against the most significant byte of the address bus.
These bits are used to compare against the least significant byte of the address bus. These bits may
be excluded from being used in the match if BK0ALE = 0.
These bits are compared to the most significant byte of the data bus or the most significant byte of the
address bus in dual address modes. BKEN[1:0], BKDBE, and BKMBH control how this byte will be used
in the breakpoint comparison.
These bits are compared to the least significant byte of the data bus or the least significant byte of the
address bus in dual address modes. BKEN[1:0], BKDBE, BK1ALE, and BKMBL control how this byte
will be used in the breakpoint comparison.
Table 49 Breakpoint Read/Write Control
BK1RWE BK1RW BK0RWE BK0RW Read/Write Selected
––0X
R/W
is don’t care for full mode or dual mode
BKP0
––10R/W
is write for full mode or dual mode BKP0
––11R/W
is read for full mode or dual mode BKP0
0X––R/W
is don’t care for dual mode BKP1
10––R/W
is write for dual mode BKP1
11––R/W
is read for dual mode BKP1
BRKAH — Breakpoint Address Register, High Byte $0022
Bit 7 6 5 4 3 2 1 Bit 0
Bit 15 14 13 12 11 10 9 Bit 8
RESET: 0 0 0 0 0 0 0 0
BRKAL — Breakpoint Address Register, Low Byte $0023
Bit 7 6 5 4 3 2 1 Bit 0
Bit 7 6 5 4 3 2 1 Bit 0
RESET: 0 0 0 0 0 0 0 0
BRKDH — Breakpoint Data Register, High Byte $0024
Bit 7 6 5 4 3 2 1 Bit 0
Bit 15 14 13 12 11 10 9 Bit 8
RESET: 0 0 0 0 0 0 0 0
BRKDL — Breakpoint Data Register, Low Byte $0025
Bit 7 6 5 4 3 2 1 Bit 0
Bit 7 6 5 4 3 2 1 Bit 0
RESET: 0 0 0 0 0 0 0 0