Freescale Semiconductor, Inc.

ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005

Freescale Semiconductor, Inc.

OnCE™ Module

ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005

12.11.4 Returning from Debug Mode to Normal Mode

There are two cases for returning from the debug mode. In Example 12-7, control will be returned to the program that was running before debug was initiated, and in Example 12-8, the registers will be changed to jump to a different program. There is no acknowledgment on the DSO pin when the chip leaves the OnCE mode following a GO, EX. This is a special case of the “write a register” option.

Example 12-7. Returning from Debug Mode to Normal Mode—OnCE

1.Send the command WRITE OPDBR with no GO and no EX (OnCE command = 00001001). ODEC selects the OPDBR as the destination for serial data. Also, ODEC selects the on-chip PAB register as the source for the PAB bus. After the PAB was driven, an acknowledge is issued to the command controller.

2.Wait for acknowledge on DS line.

3.Send the 16 bits of the saved PGDB value. After all 16 bits have been received, the PDB drives the OPDBR. ODEC generates PRNEW, so the entire chip loads the opcode. An acknowledge is issued to the command controller.

4.Wait for acknowledge on DS line.

5.Send the command WRITE OPDBR with GO and EX (OnCE command = 01101001). ODEC selects OPDBR as the destination for serial data.

6.Wait for acknowledge on DS line.

7.Send the 16 bits of the saved OPDBR value. After all 16 bits have been received, the PDB drives the OPDBR. ODEC releases the chip form the halt state, and the debug mode bit in OSR is cleared. The chip continues to execute instructions until a debug mode condition occurs.

Example 12-8. Jump to a New Program—Go from Address $xxxx

1.Send the command WRITE OPDBR with no GO and no EX (OnCE command = 00001001). ODEC selects OPDBR as the destination for serial data.

2.Wait for acknowledge on DS line.

3.Send 16 bits of the opcode of a two-word jump instruction instead of the saved OPGDBR (instruction latch) value. After all the 16 bits have been received, the PDB drives the OPDBR. ODEC causes the DSP to load the opcode. An acknowledge is issued to the command controller.

4.Wait for acknowledge on DS line.

5.Send the command WRITE OPDBR with GO and EX (OnCE command = 01101001). ODEC selects OPDBR as the destination for serial data.

6.Wait for acknowledge on DS line.