MC9S12XD256MAL Datasheet, PDF (762/1348 Pages) Freescale Semiconductor, Inc – Freescale’s Scalable Controller Area Network

Chapter 20 S12X Debug (S12XDBGV3) Module
Table 20-27. DBGXCTL Field Descriptions (continued)
Field
4
BRK
3
RW
2
RWE
1
SRC
0
COMPE
Description
Break — This bit controls whether a comparator match terminates a debug session immediately,
independent of state sequencer state. To generate an immediate breakpoint the module breakpoints must be
enabled using the DBGC1 bits DBGBRK[1:0].
0 The debug session termination is dependent upon the state sequencer and trigger conditions.
1 A match on this channel terminates the debug session immediately; breakpoints if active are generated,
tracing, if active, is terminated and the module disarmed.
Read/Write Comparator Value Bit — The RW bit controls whether read or write is used in compare for the
associated comparator. The RW bit is not used if RWE = 0.
0 Write cycle will be matched
1 Read cycle will be matched
Read/Write Enable Bit — The RWE bit controls whether read or write comparison is enabled for the
associated comparator. This bit is not useful for tagged operations.
0 Read/Write is not used in comparison
1 Read/Write is used in comparison
Determines mapping of comparator to S12XCPU or XGATE
0 The comparator is mapped to S12XCPU buses
1 The comparator is mapped to XGATE address and data buses
Determines if comparator is enabled
0 The comparator is not enabled
1 The comparator is enabled for state sequence triggers or tag generation
Table 20-28 shows the effect for RWE and RW on the comparison conditions. These bits are not useful for
tagged operations since the trigger occurs based on the tagged opcode reaching the execution stage of the
instruction queue. Thus these bits are ignored if tagged triggering is selected.
Table 20-28. Read or Write Comparison Logic Table
RWE Bit
0
0
1
1
1
1
RW Bit
x
x
0
0
1
1
RW Signal
0
1
0
1
0
1
Comment
RW not used in comparison
RW not used in comparison
Write data bus
No match
No match
Read data bus
MC9S12XDP512 Data Sheet, Rev. 2.21
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