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Chapter 8 S12X Debug (S12XDBGV3) Module
MC9S12XE-Family Reference Manual Rev. 1.07
Freescale Semiconductor
337
8.4.5.3
Trace Buffer Organization
Referring to
Table 8-42
. An X prefix denotes information from the XGATE module, a C prefix denotes
information from the CPU12X. ADRH, ADRM, ADRL denote address high, middle and low byte
respectively. INF bytes contain control information (R/W, S/D etc.). The numerical suffix indicates which
tracing step. The information format for Loop1 Mode and PurePC Mode is the same as that of Normal
Mode. Whilst tracing from XGATE or CPU12X only, in Normal or Loop1 modes each array line contains
2 data entries, thus in this case the DBGCNT[0] is incremented after each separate entry. In Detail mode
DBGCNT[0] remains cleared whilst the other DBGCNT bits are incremented on each trace buffer entry.
XGATEandCPU12XCOFsoccurindependentlyofeachotherandtheprofileofCOFsforthetwosources
is totally different. When both sources are being traced in Normal or Loop1 mode, for each COF from one
source, there may be many COFs from the other source, depending on user code. COF events could occur
far from each other in the time domain, on consecutive cycles or simultaneously. When a COF occurs in
either source (S12X or XGATE) a trace buffer entry is made and the corresponding CDV or XDV bit is
set. The current PC of the other source is simultaneously stored to the trace buffer even if no COF has
occurred, in which case CDV/XDV remains cleared indicating the address is not associated with a COF,
but is simply a snapshot of the PC contents at the time of the COF from the other source.
Single byte data accesses in Detail Mode are always stored to the low byte of the trace buffer (CDATAL
or XDATAL) and the high byte is cleared. When tracing word accesses, the byte at the lower address is
always stored to trace buffer byte3 and the byte at the higher address is stored to byte2
Table 8-42. Trace Buffer Organization
Mode
8-Byte Wide Word Buffer
7
6
5
4
3
2
1
0
XGATE
Detail
CXINF1
CADRH1
CADRM1
CADRL1
XDATAH1
XDATAL1
XADRM1
XADRL1
CXINF2
CADRH2
CADRM2
CADRL2
XDATAH2
XDATAL2
XADRM2
XADRL2
CPU12X
Detail
CXINF1
CADRH1
CADRM1
CADRL1
CDATAH1
CDATAL1
XADRM1
XADRL1
CXINF2
CADRH2
CADRM2
CADRL2
CDATAH2
CDATAL2
XADRM2
XADRL2
Both
Other Modes
XINF0
XPCM0
XPCL0
CINF0
CPCH0
CPCM0
CPCL0
XINF1
XPCM1
XPCL1
CINF1
CPCH1
CPCM1
CPCL1
XGATE
Other Modes
XINF1
XPCM1
XPCL1
XINF0
XPCM0
XPCL0
XINF3
XPCM3
XPCL3
XINF2
XPCM2
XPCL2
CPU12X
Other Modes
CINF1
CPCH1
CPCM1
CPCL1
CINF0
CPCH0
CPCM0
CPCL0
CINF3
CPCH3
CPCM3
CPCL3
CINF2
CPCH2
CPCM2
CPCL2