Motorola DSP56309 User Manual page 294

10.12.3 Saving Pipeline Information
The debugging activity is accomplished by means of DSP56300 core instructions
supplied from the external command controller. Therefore, the current state of the
DSP56300 core pipeline must be saved prior to starting the debug activity and the state
must be restored prior to returning to normal mode. Here is the description of the save
procedure (it assumes that ENABLE_ONCE has been executed and Debug mode has
been entered and verified, as described in Section 10.12.1ÑChecking Whether the Chip
Has Entered Debug Mode):
1. Select shift-DR. Shift in the ÒRead PDBÓ. Pass through update-DR.
2. Select shift-DR. Shift out the 24 bit OPDB register. Pass through update-DR.
3. Select shift-DR. Shift in the ÒRead PILÓ. Pass through update-DR.
4. Select shift-DR. Shift out the 24 bit OPILR register. Pass through update-DR.
Note that there is no need to verify acknowledge between steps 1 and 2, as well as 3 and
4, because completion is guaranteed by design.
10.12.4 Reading the Trace Buffer
An optional step during debugging activity is reading the information associated with
the trace buffer in order to enable an external program to reconstruct the full trace of the
executed program. In the following description of the read trace buffer procedure, it is
assumed that all actions described in Saving Pipeline Information have been executed.
1. Select shift-DR. Shift in the ÒRead PABFRÓ. Pass through update-DR.
2. Select shift-DR. Shift out the 16 bit OPABFR register. Pass through update-DR.
3. Select shift-DR. Shift in the ÒRead PABDRÓ. Pass through update-DR.
4. Select shift-DR. Shift out the 16 bit OPABDR register. Pass through update-DR.
5. Select shift-DR. Shift in the ÒRead PABEXÓ. Pass through update-DR.
6. Select shift-DR. Shift out the 16 bit OPABEX register. Pass through update-DR.
7. Select shift-DR. Shift in the ÒRead FIFOÓ. Pass through update-DR.
8. Select shift-DR. Shift out the 17 bit FIFO register. Pass through update-DR.
9. Repeat steps 7 and 8 for the entire FIFO (12 times).
MOTOROLA DSP56309UM/D
On-Chip Emulation Module
OnCE Module Examples
10-25