MC9S12P128 Datasheet, PDF (163/564 Pages) Freescale Semiconductor, Inc – S12 Microcontrollers

Table 6-10. ABCM Encoding
ABCM
Description
11
Reserved⁽¹⁾
1. Currently defaults to Comparator A, Comparator B disabled
S12S Debug Module (S12SDBGV2)
6.3.2.5 Debug Trace Buffer Register (DBGTBH:DBGTBL)
Address: 0x0024, 0x0025
15
14
13
12
11
10
9
R
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9
W
POR X X X X X X X
Other
Resets
—
—
—
—
—
—
—
8
Bit 8
X
—
7
Bit 7
X
—
6
Bit 6
X
—
5
Bit 5
X
—
4
Bit 4
X
—
3
Bit 3
X
—
2
Bit 2
X
—
1
Bit 1
X
—
0
Bit 0
X
—
Figure 6-7. Debug Trace Buffer Register (DBGTB)
Read: Only when unlocked AND unsecured AND not armed AND TSOURCE set.
Write: Aligned word writes when disarmed unlock the trace buffer for reading but do not affect trace buffer
contents.
Table 6-11. DBGTB Field Descriptions
Field
15–0
Bit[15:0]
Description
Trace Buffer Data Bits — The Trace Buffer Register is a window through which the 20-bit wide data lines of the
Trace Buffer may be read 16 bits at a time. Each valid read of DBGTB increments an internal trace buffer pointer
which points to the next address to be read. When the ARM bit is set the trace buffer is locked to prevent reading.
The trace buffer can only be unlocked for reading by writing to DBGTB with an aligned word write when the
module is disarmed. The DBGTB register can be read only as an aligned word, any byte reads or misaligned
access of these registers return 0 and do not cause the trace buffer pointer to increment to the next trace buffer
address. Similarly reads while the debugger is armed or with the TSOURCE bit clear, return 0 and do not affect
the trace buffer pointer. The POR state is undefined. Other resets do not affect the trace buffer contents.
6.3.2.6 Debug Count Register (DBGCNT)
Address: 0x0026
7
6
5
4
3
2
1
0
R TBF
0
CNT
W
Reset
—
—
—
—
—
—
—
—
POR
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 6-8. Debug Count Register (DBGCNT)
Read: Anytime
Write: Never
S12P-Family Reference Manual, Rev. 1.12
Freescale Semiconductor
163