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Altera_Forum's avatar
Altera_Forum
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15 years ago

EPC2 to Cyclone Loading Issues

I have an EPC2 EEPROM and Cyclone interfaced with each other and I am having issues with the EPC2 loading the Cyclone. I have prototyped this interface and had it working with no problems but when the design was put on copper the interface is acting really strange.

The Cyclone never gets loaded on startup until I touch Pin 9 (NCS) of the EPC2 device with a probe or my finger. From what I can gather is that I am adding very little capacitance to that pin and which in turn, loads my firmware to the FPGA. I don't know why this is or how (with good design practice) this can be fixed. Any help would be appreciated.

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

    It's the strangest thing, but I got it working. I recompiled the firmware (.jbc file) using the latest Quartus II software, v10.0 SP1, and everything works now. :unsure: If I ever have a problem with the EPC2 loading the Cyclone I will go back to the firmware first from now on. This is confusing to me but it seems like the best debugging strategy.