XC912BC32CFU8 Motorola Semiconductor Products, XC912BC32CFU8 Datasheet - Page 327

• Manufacturer Part Number: XC912BC32CFU8
• Description: M68HC12B Family Data Sheet
• Manufacturer: Motorola Semiconductor Products

18.3.9 BDM CCR Holding Register
18.4 Breakpoints
18.4.1 Breakpoint Modes
M68HC12B Family — Rev. 8.0
MOTOROLA
The CCRSAV register is used to save the state of the condition code register
(CCR) of the user’s program when entering BDM. It is also used for temporary
storage in the BDM firmware. The register is initialized by the firmware to equal the
CPU CCR register.
Hardware breakpoints are used to debug software on the MCU by comparing
actual address and data values to predetermined data in setup registers. A
successful comparison places the CPU in background debug mode (BDM) or
initiates a software interrupt (SWI).
Breakpoint features designed into the MCU include:
Three modes of operation determine the type of breakpoint in effect.
Breakpoints do not occur when BDM is active.
1. Dual address-only breakpoints, each of which causes a software interrupt
2. Single full-feature breakpoint which causes the part to enter background
3. Dual address-only breakpoints, each of which causes the part to enter BDM
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Address: $FF06
Reset:
Read:
Write:
Mode selection for BDM or SWI generation
Program fetch tagging for cycle of execution breakpoint
Second address compare in dual address modes
Range compare by disable of low byte address
Data compare in full feature mode for non-tagged breakpoint
Byte masking for high/low byte data compares
R/W compare for non-tagged compares
Tag inhibit on BDM TRACE
(SWI)
debug mode (BDM)
CCR7
Bit 7
Figure 18-9. BDM CCR Holding Register (CCRSAV)
0
Development Support
CCR6
6
0
CCR5
5
0
CCR4
4
0
CCR3
3
0
CCR2
2
0
Development Support
CCR1
1
0
Breakpoints
Data Sheet
CCR0
Bit 0
0
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