PowerPC and JTAG

Yes. There is an internal JTag tap that can be "tapped into" If you want to use the PPC Jtag you have to use the internal tap symbol. Also If you load via the select map you can have pins from the Xilinx route outside to the jtag pins.

I sure there are other ways also.

Steve

Is this really true? I thought the only way you could drive the JTAG pins was with external connections from other IO pins. The only reference I could find to JTAG tap is the way the PPC taps into the JTAG instruction register so the length doesn't vary depending on whether the PPC is used or not.

Could you cite a reference?

Alan Nishioka snipped-for-privacy@accom.com

Alan,

Page 260 of the PowerPC Processor Reference Guide covers JTAG for the

405PPC.

and go to the /documentation/users guides/Device Families/Virtex-II Pro/

Aust>

Right, but I think the OP was asking if you could *drive* JTAG from the PPC and I didn't think this was possible (w/o external connections).

I want to do this so I can update flash using JTAG and the internal PPC.

Alan Nishioka snipped-for-privacy@accom.com

Alan,

Since the PPC is all inside the FPGA, and you have to instatiate the JATG to get access to the PPC, I imagine you can wire it anywhere you want in the fabric....

Aust>