Datasheet

Chapter 20 S12X Debug (S12XDBGV3) Module
MC9S12XDP512 Data Sheet, Rev. 2.21
762 Freescale Semiconductor
20.3.2.7.4 Debug Match Flag Register (DBGMFR)
Read: Anytime
Write: Never
DBGMFR is visible at 0x0027 only with COMRV[1:0] = 11. It features four flag bits each mapped directly
to a channel. Should a match occur on the channel during the debug session, then the corresponding flag
is set and remains set until the next time the module is armed by writing to the ARM bit. Thus the contents
are retained after a debug session for evaluation purposes. These flags cannot be cleared by software, they
are cleared only when arming the module. A set flag does not inhibit the setting of other flags. Once a flag
is set, further triggers on the same channel have no affect.
20.3.2.8 Comparator Register Descriptions
Each comparator has a bank of registers that are visible through an 8-byte window in the S12XDBG
module register address map. Comparators A and C consist of 8 register bytes (3 address bus compare
registers, two data bus compare registers, two data bus mask registers and a control register).
Comparators B and D consist of four register bytes (three address bus compare registers and a control
register).
Each set of comparator registers is accessible in the same 8-byte window of the register address map and
can be accessed using the COMRV bits in the DBGC1 register. If the Comparators B or D are accessed
through the 8-byte window, then only the address and control bytes are visible, the 4 bytes associated with
data bus and data bus masking read as zero and cannot be written. Furthermore the control registers for
comparators B and D differ from those of comparators A and C.
Address: 0x0027
76543210
R0000MC3MC2MC1MC0
W
Reset 00000000
= Unimplemented or Reserved
Figure 20-12. Debug Match Flag Register (DBGMFR)
Table 20-26. Comparator Register Layout
0x0028 CONTROL Read/Write —
0x0029 ADDRESS HIGH Read/Write —
0x002A ADDRESS MEDIUM Read/Write —
0x002B ADDRESS LOW Read/Write —
0x002C DATA HIGH COMPARATOR Read/Write Comparator A and C only
0x002D DATA LOW COMPARATOR Read/Write Comparator A and C only
0x002E DATA HIGH MASK Read/Write Comparator A and C only
0x002F DATA LOW MASK Read/Write Comparator A and C only