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Altera_Forum
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19 years ago

Cyclone III AS configuration bizarreness

I am using a cyclone III (EP3C25F324C8N) with an EPCS16 configuration device. I am programming the configuration device through the FPGA with the serial flash loader. The problem is that the Cyc...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
18 years ago

I've had a similar problem myself with an EPCS16 and Cyclone III. It wasn't configuring so I probed the DCLK pin with a scope and it configured. Then I found that touching the pin with a screwdriver was sufficient for it to configure and if the screwdriver was there on power up then it would also work. Very strange.

Anyway, I added a 100pF capacitor between the DCLK pin and GND and it has been fine since that.

If anyone can explain this behaviour to me then please do. I would like to understand what was going on, but it's nice to have resolved the problem even if more by luck than judgement :)