MCF548x Reference Manual, Rev. 3
8-20 Freescale Semiconductor

8.4.7 Program Counter Breakpoint and Mask Registers (PBRn, PBMR)

Each PC breakpoint register (PBR, PBR1, PBR2, PBR3) defines an instruction address for use as part of
the trigger. These registers’ contents are compared with the processors program counter register when the
appropriate valid bit is set, and TDR or XTDR are configured appropriately. PBR bits are masked by
setting corresponding PBMR bits. Results are compared with the processors program counter register, as
defined in TDR or XTDR. PBR1–PBR3 are not masked. Figure 8-11 shows the PC breakpoint register.
PC breakpoint registers are accessible in supervisor mode using the WDEBUG instruction and through the
BDM port using the RDMREG and WDMREG commands using values shown in Section 8.5.3.3, “Command
Set Descriptions.”
Table 8-13 describes PBR, PBR1, PBR2, and PBR3 fields.
2 EAL1 Address enable bit: Enable address breakpoint low. The breakpoint is based on the address in the
ABLR. Trigger address = ABLR
1 EPC1 Enable PC breakpoint. If set, this bit enables the PC breakpoint for the first level trigger.
0 PCI1 Breakpoint invert. If set, this bit allows execution outside a given region as defined by
PBR/PBR1/PBR2/PBR3 and PBMR to enable a trigger. If cleared, the PC breakpoint is defined
within the region defined by PBR/PBR1/PBR2/PBR3 and PBMR.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
R CNTRAD
W
Reset0000000000000000
1514131211109876543210
R CNTRAD 0
W V1
Reset0000000000000000
Reg
Addr
CPU + 0x08 (PBR); 0x18 (PBR1); 0x1A (PBR2); 0x1B (PBR3)
1PBR0 does not have a valid bit. PBR0 is read as 0 and should be cleared.
Figure 8-11. Program Counter Breakpoint Registers (PBR, PBR1, PBR2, PBR3)
Table 8-12. TDR Field Descriptions (Continued)
Bits Name Description