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Altera_Forum's avatar
Altera_Forum
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11 years ago

EPM7128ELC84 fab/rev differences

We've been using EPM7128ELC84-200 since the 90s, shipped thousands of boards with no problems. It seems only "older" chips made in the US with 2 digit letter. 4 digit number lot number work fine and newer chips don't. I'm in the process of reviewing the datasheet and trying to get clues as to what's going on. I only have the .pof file which was compiled with an older development system prior to Quartus, or whatever it's called and hope I don't need to resurrect this project and recompile this thing. Fully understand the date and process markings as per Altera's PCN

Chased the possibility of counterfeit chips, improper programming, etc... purchased a batch of chips from ARROW here in NJ, a reputable distributor, which also don't work. Confirmed any chip with earlier date codes erases/reprograms and works

The CPLD does handle enable lines for a ROM connected to a DSP so I'm looking at startup problems, DSP access before the 7128 is "ready", powerup/reset timing, etc... but I would have thought moving to a later rev die or different fab of the 7128 would be seamless and just work.

I'm a XILINX guy and hoping someone here is familiar with this issue.

Thanks,

Phil

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

    So I've isolated the 7128, removing it from all connected devices like the DSP, ROM, etc.. and simply clocking it with a signal generator running at 100Khz to eliminate timing/speed problems or conflicts and proved this works on an older style chip. From what I learned the input clock is divided down and output to an output LED to provide a simple heartbeat to indicate it's running and newer date codes show no activity. So back on the possibility of improper programming. This isn't the 'S" JTAG version, but old school externally programmed by our vendor using a 3rd party programmer and a .pof file that's worked for many years. This programmer was proved out and working on chips era 1998, but nothing manufactured recently seems to work.

    Can anyone confirm .pof files generated for era 1998 EPM129ELC84 chips will work on the chips manufactured today?

    Thank You