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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,

Thanks, Dave, for the replies. 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. Maybe the JIC is generated with an extra byte between the firmware and HEX file for the software or something. FYI, the boot loader is the EPCS one provided by Altera. Very simple and the source is provided with the tools.

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. In my case the differences are:

Address 0x29: CONF_DONE check: 0xDF, no CONF_DONE check: 0xCF

Address 0x45: CONF_DONE check: 0xBF, no CONF_DONE check: 0xFF

Address 0x46: CONF_DONE check: 0x9F, no CONF_DONE check: 0xDF

Address 0x49: CONF_DONE check: 0x81, no CONF_DONE check: 0xA4

Address 0x4A: CONF_DONE check: 0x59, no CONF_DONE check: 0x41

Mark.