mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 704

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 19 Debug (S12XDBGV2)
19.3.1.6
Read: Anytime
Write: Never
704
0x0026
CNT[6:0]
Reset
POR
Field
6–0
W
R
1
Count Value — The CNT bits [6:0] indicate the number of valid data 64-bit data lines stored in the trace buffer.
Table 19-18
When the CNT rolls over to 0, the TBF bit in DBGSR is set and incrementing of CNT will continue in end-trigger
or mid-trigger mode. The DBGCNT register is cleared when ARM in DBGC1 is written to a 1. The DBGCNT
register is cleared by power-on-reset initialization but is not cleared by other system resets. Thus should a reset
occur during a debug session, the DBGCNT register still indicates after the reset, the number of valid trace buffer
entries stored before the reset occurred. The DBGCNT register is not decremented when reading from the trace
buffer.
TBF (DBGSR)
This applies to normal/loop1 modes when tracing from either CPU or XGATE only.
Debug Count Register (DBGCNT)
0
0
0
7
0
0
0
0
0
1
1
Unimplemented or Reserved
shows the correlation between the CNT bits and the number of valid data lines in the trace buffer.
—
0
6
CNT[6:0]
0000000
0000001
0000010
0000011
0000100
0000110
1111100
1111110
0000000
0000010
1111110
Figure 19-9. Debug Count Register (DBGCNT)
Table 19-17. DBGCNT Field Descriptions
..
..
..
MC9S12XDP512 Data Sheet, Rev. 2.17
Table 19-18. CNT Decoding Table
—
0
5
oldest data has been overwritten by most recent data
ARM bit will be cleared and the tracing session ends.
64 lines valid; if using begin-trigger alignment,
—
0
4
Description
32 bits of one line valid
1.5 lines valid
64 lines valid,
CNT
No data valid
62 lines valid
63 lines valid
Description
2 lines valid
3 lines valid
—
1 line valid
0
3
..
1
—
0
2
1
Freescale Semiconductor
—
0
1
—
0
0