S12X Debug (S12XDBGV3) Module
MC9S12XHY-Family Reference Manual, Rev. 1.01
254
Freescale Semiconductor
6.4.5.3.1
Information Byte Organization
The format of the control information byte is dependent upon the active trace mode as described below.
In Normal, Loop1, or Pure PC modes tracing of CPU12X activity, CINF is used to store control
information. In Detail Mode, CXINF contains the control information
CPU12X Information Byte
CXINF Information Byte
This describes the format of the information byte used only when tracing in Detail Mode. When tracing
from the CPU12X in Detail Mode, information is stored to the trace buffer on all cycles except opcode
fetch and free cycles. In this case the CSZ and CRW bits indicate the type of access being made by the
CPU12X.
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
CSD
CVA
0
CDV
0
0
0
0
Figure 6-23. CPU12X Information Byte CINF
Table 6-41. CINF Field Descriptions
Field
Description
7
CSD
Source Destination Indicator — This bit indicates if the corresponding stored address is a source or destination
address. This is only used in Normal and Loop1 mode tracing.
0 Source address
1 Destination address
6
CVA
Vector Indicator — This bit indicates if the corresponding stored address is a vector address.. Vector addresses
are destination addresses, thus if CVA is set, then the corresponding CSD is also set. This is only used in Normal
and Loop1 mode tracing. This bit has no meaning in Pure PC mode.
0 Indexed jump destination address
1 Vector destination address
4
CDV
Data Invalid Indicator — This bit indicates if the trace buffer entry is invalid. It is only used when tracing from
both sources in Normal, Loop1 and Pure PC modes, to indicate that the CPU12X trace buffer entry is valid.
0 Trace buffer entry is invalid
1 Trace buffer entry is valid
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
CSZ
CRW
Figure 6-24. Information Byte CXINF
Table 6-42. CXINF Field Descriptions
Field
Description
6
CSZ
Access Type Indicator — This bit indicates if the access was a byte or word size access.This bit only contains
valid information when tracing CPU12X activity in Detail Mode.
0 Word Access
1 Byte Access
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