Motorola 24-Bit Digital Signal Processor, DSP56000 manual Motorola

USING THE OnCE

The OnCE controller selects GDB as source for serial data.

6.ACK

7.CLK

10.11.3Displaying X Memory Area Starting From Address XXXX This command uses R0 to minimize serial traffic.

1.Send command WRITE PDB REGISTER, GO, no EX (01001001). The OnCE controller selects PDB as destination for serial data.

2.ACK

3.Send the 24-bit DSP56K opcode: “MOVE R0,x:OGDB”

After 24 bits have been received the PDB register drives the PDB. The OnCE con- troller releases the chip from the debug mode and the contents of R0 are loaded in the GDB REGISTER. The signal that marks the end of the instruction returns the chip to the debug mode.

4.ACK

5.Send command READ GDB REGISTER (10001001)

The OnCE controller selects GDB as source for serial data.

6.ACK

7.CLK

The external command controller generates 24 clocks that shift out the contents of the GDB register. The value of R0 is thus saved and should be restored before ex- iting the debug mode.

8.Send command WRITE PDB REGISTER, no GO, no EX (00001001) OnCE controller selects PDB as destination for serial data.

9.ACK

10.Send the 24-bit DSP56K opcode: “MOVE #$xxxx,R0”

After 24 bits have been received, the PDB register drives the PDB. The OnCE con- troller causes the processor to load the opcode.

11.ACK

12.Send command WRITE PDB REGISTER, GO, no EX (01001001) The OnCE controller selects PDB as destination for serial data.

13.ACK

14.Send the 24-bit 2nd word of: “MOVE #$xxxx,R0” (the xxxx field).

After 24 bits have been received, the PDB register drives the PDB. The OnCE con-

MOTOROLA ON-CHIP EMULATION (OnCE) 10 - 23