mc68hc912bl16 Freescale Semiconductor, Inc, mc68hc912bl16 Datasheet - Page 126

• Manufacturer Part Number: mc68hc912bl16
• Description: 16-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

BRKAH — Breakpoint Address Register, High Byte
BRKAL — Breakpoint Address Register, Low Byte
BRKDH — Breakpoint Data Register, High Byte
BRKDL — Breakpoint Data Register, Low Byte
15.4 Instruction Tagging
126
Power-on
Power-on
Power-on
Power-on
RESET:
RESET:
RESET:
RESET:
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 in full breakpoint mode 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 in full breakpoint mode 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.
The instruction queue and cycle-by-cycle CPU activity can be reconstructed in real time or from trace
history that was captured by a logic analyzer. However, the reconstructed queue cannot be used to stop
the CPU at a specific instruction, because execution has already begun by the time an operation is vis-
ible outside the MCU. A separate instruction tagging mechanism is provided for this purpose.
Executing the BDM TAGGO command configures two MCU pins for tagging. Tagging information is
latched on the falling edge of ECLK along with program information as it is fetched. Tagging is allowed
Bit 15
Bit 15
Bit 7
Bit 7
Bit 7
Bit 7
Bit 7
Bit 7
0
0
0
0
After a power-on reset, registers BRKAH, BRKAL, BRKDH, and BRKDL are
cleared but these registers are not affected by normal resets.
14
14
6
0
6
6
0
6
0
6
6
0
Freescale Semiconductor, Inc.
For More Information On This Product,
13
13
5
0
5
5
0
5
0
5
5
0
Go to: www.freescale.com
12
12
4
0
4
4
0
4
0
4
4
0
NOTE
11
11
3
0
3
3
0
3
0
3
3
0
10
10
2
0
2
2
0
2
0
2
2
0
1
9
0
1
1
0
1
9
0
1
1
0
MC68HC912BL16TS/D
MC68HC912BL16
Bit 0
Bit 8
Bit 0
Bit 0
Bit 0
Bit 8
Bit 0
Bit 0
0
0
0
0
$0022
$0023
$0024
$0025