
Functional Description and Application Information
S12S Debug (S12SDBGV1) Module
MM912F634
Freescale Semiconductor
225
4.31.3.2.7.4
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 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 comparator matches on the same channel in the same session have no affect on that flag.
4.31.3.2.8
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.
Table 287. Debug Match Flag Register (DBGMFR)
Address: 0x0027
7
6
5
432
10
R
0
MC2
MC1
MC0
W
Reset
0
000
00
0
Table 288. 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