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CHAPTER 2 DEPENDENCE FUNCTIONS
2.2.8 Real-time Trace
While execution a program, the address, data and status information, and the data
sampled by an external probe can be sampled in machine cycle units and stored in the
trace buffer. This function is called real-time trace.
In-depth analysis of a program execution history can be performed using the data
recorded by real-time trace.
There are two types of trace sampling: single trace, which traces from the start of
executing the program until the program is suspended, and multi trace, which starts
tracing when an event occurs.
■ Trace Buffer
The data recorded by sampling in machine cycle units, is called a frame.
The trace buffer can store 32K frames (32768). Since the trace buffer has a ring structure, when it becomes
full, it automatically returns to the start to overwrite existing data.
■ Trace Data
Data sampled by the trace function is called trace data.
The following data is sampled:
• Address
•Data
• Status Information
- Access status: Read/Write/Internal access, etc.
- Device status: Instruction execution, Reset, Hold, etc.
- Queue status: Count of remaining bytes of instruction queue, etc.
- Data valid cycle information: Data valid/invalid
(Since the data signal is shared with other signals, it does not always output data. Therefore, the trace
samples information indicating whether or not the data is valid.)
• External probe data
• Sequencer execution level
■ Data Not Traced
The following data does not leave access data in the trace buffer.
- Data after tool hold
The F
2
MC-16/16L/16LX/16H/16F family execute the following operation immediately after a break, etc.,
lets MCU suspend (a tool hold). This data is not displayed because it is deleted from the trace buffer.
- Access to address 100
- Access to FFFFDC to FFFFFF
- Portion of access data while native mode.
When operating in the native mode, the F
2
MC-16/16L/16LX/16H/16F family of chips sometime performs
simultaneous multiple bus operations internally. However, in this emulator, monitoring of the internal
ROM bus takes precedence. Therefore, other bus data being accessed simultaneously may not be sampled
(in the debugging mode, all operations are sampled).