Motorola DSP56309 User Manual page 295

On-Chip Emulation Module
OnCE Module Examples
Note: The user must read the entire FIFO, since each read increments the FIFO
pointer, thus pointing to the next FIFO location. At the end of this procedure,
the FIFO pointer points back to the beginning of the FIFO.
The information that has been read by the external command controller now contains
the address of the newly fetched instruction, the address of the instruction currently on
the PDB, the address of the instruction currently on the instruction latch, as well as the
addresses of the last 12 instructions that have been executed and are change of flow. A
user program can now reconstruct the flow of a full trace based on this information and
on the original source code of the currently running program.
10.12.5 Displaying a Specified Register
To display a specified register, the DSP56300 must be in debug mode and all actions
described in Section 10.12.3ÑSaving Pipeline Information have been executed. The
sequence of actions is as follows:
1. Select shift-DR. Shift in the ÒWrite PDB with GO no-EXÓ. Pass through
update-DR.
2. Select shift-DR. Shift in the 24-bit opcode: ÒMOVE reg, X:OGDBÓ. Pass through
update-DR to actually write OPDBR and thus begin executing the MOVE
instruction.
3. Wait for DSP to reenter debug mode (wait for DE or poll core status).
4. Select shift-DR and shift in ÒREAD GDB REGISTERÓ. Pass through update-DR.
This step selects OGDBR as the data register for the read.
5. Select shift-DR. Shift out the OGDBR contents. Pass through update-DR. Wait for
next command.
10.12.6 Displaying X Memory Area Starting at Address $xxxx
The DSP56309 must be in debug mode and all actions described in
Section 10.12.3ÑSaving Pipeline Information must have been executed. Since R0 is
used as pointer for the memory, R0 is saved first. The sequence of actions is as follows:
1. Select shift-DR. Shift in the ÒWrite PDB with GO no-EXÓ. Pass through
update-DR.
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