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Altera_Forum's avatar
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 whole configuration from the EPCS and then toggles nStatus and starts over. Once upon a time I think there was an option to get the FPGA to ignore CONF_DONE but it doesn't seem to be there anymore in 12.1SP1. I've checked all the usual stuff (MSEL pins set correctly, etc) and the only suspicious thing I can find is the floating CONF_DONE pin. Does anyone know if this will scupper configuration from EPCS?

Thanks,

Mark.

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

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    I got there in the end by abandoning the JIC method, generating a RPD binary file with CONF_DONE checking off, reversing all the bits in every byte, making an SREC, and concatenating my software to the end. Then it all came right.

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    Nice! :)

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    Maybe the JIC is generated with an extra byte between the firmware and HEX file for the software or something.

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    I've noticed slight differences in .rbf, .rpd, etc bytes. Since there's no official documentation on the format, its a little difficult to know "what matters".

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    For those who might be interested, there is of course very little difference between the firmware with CONF_DONE checking enabled (the default behaviour) and with CONF_DONE checking disabled.

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    Thanks for posting your solution!

    Cheers,

    Dave