MMC2107 - Freescale Semiconductor

Freescale Semiconductor, Inc.
JTAG Test Access Port and OnCE
Functional Description
21.14.8.1 OnCE Trace Counter
The OnCE trace counter register (OTC) is a 16-bit counter that allows
more than one instruction to be executed in real time before the device
returns to debug mode. This feature helps the software developer debug
sections of code that are time-critical. The trace counter also enables the
user to count the number of instructions executed in a code segment.
nc...
DSCK
DSO
DSI
OnCE TRACE COUNTER
DEC
END
OF
INSTRUCTION
Freescale Semiconductor, I
Figure 21-12. OnCE Trace Logic Block Diagram
The OTC register can be read, written, or cleared through the OnCE
serial interface. If N instructions are to be executed before entering
debug mode, the trace counter should be loaded with N – 1. N must not
equal zero unless the sequential breakpoint control capability is being
used. In this case a value of zero (indicating a single instruction) is
allowed.
A hardware reset clears the OTC.
COUNT = 0
ISTRACE
MMC2107 – Rev. 2.0
Technical Data
MOTOROLA JTAG Test Access Port and OnCE 573
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