S12S Debug Module (S12SDBGV2)
S12P-Family Reference Manual, Rev. 1.13
168
Freescale Semiconductor
6.3.2.7.4
Debug Match Flag Register (DBGMFR)
Read: If COMRV[1:0] = 11
Write: Never
DBGMFR is visible at 0x0027 only with COMRV[1:0] = 11. It features 3 ag bits each mapped directly
to a channel. Should a match occur on the channel during the debug session, then the corresponding ag
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 ags cannot be cleared by software, they
are cleared only when arming the module. A set ag does not inhibit the setting of other ags. Once a ag
is set, further comparator matches on the same channel in the same session have no affect on that ag.
6.3.2.8
Comparator Register Descriptions
Each comparator has a bank of registers that are visible through an 8-byte window in the DBG module
register address map. Comparator A consists of 8 register bytes (3 address bus compare registers, two data
bus compare registers, two data bus mask registers and a control register). Comparator B consists of four
register bytes (three address bus compare registers and a control register). Comparator C consists of four
register bytes (three address bus compare registers and a control register).
Each set of comparator registers can be accessed using the COMRV bits in the DBGC1 register.
Unimplemented registers (e.g. Comparator B data bus and data bus masking) read as zero and cannot be
written. The control register for comparator B differs from those of comparators A and C.
6.3.2.8.1
Debug Comparator Control Register (DBGXCTL)
The contents of this register bits 7 and 6 differ depending upon which comparator registers are visible in
the 8-byte window of the DBG module register address map.
Address: 0x0027
76543210
R
00000
MC2
MC1
MC0
W
Reset
00000000
= Unimplemented or Reserved
Figure 6-12. Debug Match Flag Register (DBGMFR)
Table 6-21. Comparator Register Layout
0x0028
CONTROL
Read/Write
Comparators A,B and C
0x0029
ADDRESS HIGH
Read/Write
Comparators A,B and C
0x002A
ADDRESS MEDIUM
Read/Write
Comparators A,B and C
0x002B
ADDRESS LOW
Read/Write
Comparators A,B and C
0x002C
DATA HIGH COMPARATOR
Read/Write
Comparator A only
0x002D
DATA LOW COMPARATOR
Read/Write
Comparator A only
0x002E
DATA HIGH MASK
Read/Write
Comparator A only
0x002F
DATA LOW MASK
Read/Write
Comparator A only