Motorola DSP56309 User Manual page 297

On-Chip Emulation Module
OnCE Module Examples
10.12.7 Returning from Debug to Normal Mode (Same Program)
In this case, you have finished examining the current state of the machine, changed some
of the registers, and wish to return and continue execution of the same program from the
point where it stopped. Therefore, you must restore the pipeline of the machine and
enable normal instruction execution. The sequence of actions to do so is listed below:
1. Select shift-DR. Shift in the ÒWrite PDB with no-GO no-EXÓ. Pass through
update-DR.
2. Select shift-DR. Shift in the 24 bits of saved PIL (instruction latch value). Pass
through update-DR to actually write the instruction latch.
3. Select shift-DR. Shift in the ÒWrite PDB with GO and EXÓ. Pass through
update-DR.
4. Select shift-DR. Shift in the 24 bits of saved PDB. Pass through update-DR to
actually write the PDB. At the same time the internally saved value of the PAB is
driven back from the PABFR register onto the PAB, the ODEC releases the chip
from debug mode, and the normal flow of execution is continued.
10.12.8 Returning from Debug to Normal Mode (New Program)
In this case, you have finished examining the current state of the machine, changed some
of the registers, and wish to start the execution of a new program (the GOTO command).
Therefore, you must force a Òchange-of-flowÓ to the starting address of the new program
($xxxx). The sequence of actions to do so is listed below:
1. Select shift-DR. Shift in the ÒWrite PDB with no-GO no-EXÓ. Pass through
update-DR.
1. Select shift-DR. Shift in the 24-bit Ò$0AF080Ó which is the opcode of the JUMP
instruction. Pass through update-DR to actually write the instruction latch.
2. Select shift-DR. Shift in the ÒWrite PDB-GO-TO with GO and EXÓ. Pass through
update-DR.
3. Select shift-DR. Shift in the 16 bit of Ò$xxxxÓ. Pass through update-DR to actually
write the PDB. At this time the ODEC releases the chip from debug mode and the
execution is started from the address $xxxx.
If the device enters debug mode during a DO LOOP, REP instruction, or other
Note:
special cases such as interrupt processing, STOP, WAIT, or conditional
branching, you must first reset the DSP56300 and then proceed with the
execution of the new program.
10-28 DSP56309UM/D MOTOROLA