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Altera_Forum
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12 years ago

Is CONF_DONE read by the FPGA?

Hi All, I'm debugging a board with a Cyclone IV device where the CONF_DONE pin was inadvertently left floating. The FPGA configures fine over JTAG but when configuring from EPCS it reads the w...
Altera_Forum's avatar
Altera_Forum
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12 years ago

Hi Dave,

Thanks for the reply.

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perhaps the FPGA does an internal check of CONF_DONE.

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This would seem to be the case. I took a similar board (Cyclone III, EPCS64) and removed the pull-up from the CONF_DONE line. The behaviour became the same: downloads all the configuration data from the EPCS64, toggles the nStatus line, and starts over. Repeat. I put the resistor back and it configured fine. So it looks like the CONF_DONE line is bidirectional and the FPGA itself checks the status and restarts configuration if there's no pull-up and the line doesn't go high.

I haven't had any luck with the option you pointed out but I'll persevere with it some more. It's my only hope...

Thanks,

Mark.