Datasheet

Development Support
M68HC12B Family Data Sheet, Rev. 9.1
302 Freescale Semiconductor
BK0ALE — Breakpoint 0 Range Control Bit
Valid in all modes
0 = BRKAL is not used to compare to the address bus.
1 = BRKAL is used to compare to the address bus.
18.4.2.2 Breakpoint Control Register 1
This register is read/write in all modes.
BKDBE — Enable Data Bus Bit
Enables comparing of address or data bus values using the BRKDH/L registers.
0 = BRKDH/L registers are not used in any comparison.
1 = BRKDH/L registers are used to compare address or data (depending upon the mode selections
BKEN1 and BKEN0).
BKMBH — Breakpoint Mask High Bit
Disables the comparing of the high byte of data when in full breakpoint mode. Used in conjunction with
the BKDBE bit (which should be set)
0 = High byte of data bus (bits 15:8) are compared to BRKDH.
1 = High byte is not used in comparisons.
BKMBL — Breakpoint Mask Low Bit
Disables the matching of the low byte of data when in full breakpoint mode. Used in conjunction with
the BKDBE bit (which should be set)
0 = Low byte of data bus (bits 7–0) are compared to BRKDL.
1 = Low byte is not used to in comparisons.
BK1RWE — R/W
Compare Enable Bit
Enables the comparison of the R/W
signal to further specify what causes a match. This bit is NOT
useful in program breakpoints or in full breakpoint mode. This bit is used in conjunction with a second
address in dual address mode when BKDBE = 1.
0 = R/W
is not used in comparisons.
1 = R/W
is used in comparisons.
Table 18-8. Breakpoint Address Range Control
BK1ALE BK0ALE Address Range Selected
— 0 Upper 8-bit address only for full mode or dual mode BKP0
— 1 Full 16-bit address for full mode or dual mode BKP0
0 — Upper 8-bit address only for dual mode BKP1
1 — Full 16-bit address for dual mode BKP1
Address: $0021
Bit 7654321Bit 0
Read:
0 BKDBE BKMBH BKMBL BK1RWE BK1RW BK0RWE BK0RW
Write:
Reset:00000000
Figure 18-11. Breakpoint Control Register 1 (BRKCT1)