Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

What is Timing between nCEO and DCLK in a multi-device AS Configuration ?

Is there timing requirements between nCEO and DCLK when configuring two FPGA's from one EPCS device? The master device (the first FPGA configured) operates in an AS configuration mode and once ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

Thanks Jim. I will certainly have a look at the document you referenced.

I might be able to help with your problem, if I am understanding it correctly.

You have one Cyc III being programmed AS from an EPCS device, and you do not

see the nCS line transition, yes? I would not expect the nCS line to transition I

would have it pulled to GND through a 10K Ohm resistor. Some diagrams show it

tied directly to GND, but I see the pull down resistor in the diagrams explaining

the arrangement that uses a 10 pin programming cable to program the EPCS.

http://www.altera.com/literature/hb/cyc3/cyc3_ciii51016.pdf

Excuse me if I am misunderstanding your issue.

I have had some mystery with when I program the EPCS with my programming cable

as to whether I need to remove the programming cable to allow the FPGA configuration

to start. Sometimes I can leave it in. Sometimes I have to disconnect it (?).