MMC2001
REFERENCE MANUAL
OnCE DEBUG MODULE
MOTOROLA
16-9
SQC — Sequential Control
The SQC field allows memory breakpoint B and trace occurrences to be suspended
until a qualifying event occurs. This field is cleared on test logic reset.
DR — CPU Debug Request Control
This control bit is used to request the CPU to enter debug mode unconditionally. The
CPU indicates that debug mode has been entered via the PM bits in the OnCE status
register. Once the CPU enters debug mode, it returns there even with a write to the
OCMR with GO and EX set until the DR bit is cleared. This bit is cleared on test logic
reset.
IDRE — Internal Debug Request Enable
This control bit is used to enable internally generated debug requests. The internal
debug request input to the OnCE control logic (IDR) may not be used in all implemen-
tations. In some implementations, the IDR control input may be connected and used
as an additional hardware debug request. This bit is cleared on test logic reset.
0 =
Disable IDR input operation
1 =
Enable IDR input operation
TME — Trace Mode Enable
The TME control bit enables the OnCE trace mode operation (see
16.9 OnCE Trace
Logic
). This bit is cleared on test logic reset. Trace operation is also affected by the
SQC field described above.
0 =
Disable trace operation
1 =
Enable trace operation
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SQC[1:0]
Meaning
Disable sequential control operation. Memory breakpoints and trace operation are unaf-
fected by this field.
Suspend normal trace counter operation until a breakpoint condition occurs for memory
breakpoint B. If this mode is selected, memory breakpoint B occurrences no longer cause
a breakpoint request to be generated. Instead, trace counter comparisons are suspended
until the first memory breakpoint B occurrence. After the first memory breakpoint B occur-
rence, trace counter control is released to perform normally (assuming TME is set). This
allows a sequence of breakpoint conditions to be specified prior to trace counting.
Qualify memory breakpoint B matches with a breakpoint occurrence for memory break-
point A. If this bit is set, memory breakpoint A occurrences no longer cause a breakpoint
request to be generated. Instead, memory breakpoint B comparisons are suspended until
the first memory breakpoint A occurrence. After the first memory breakpoint A occur-
rence, memory breakpoint B is enabled to perform normally. This allows a sequence of
breakpoint conditions to be specified.
Combine the qualifications specified by the 01 and 10 encodings of this field. In this
mode, no breakpoint requests are generated, and trace count operation is enabled (if
TME is set) once a memory breakpoint B occurrence follows a memory breakpoint A
occurrence.