(pictures will follow)

I wanted to create software for this programmer so that it could again be used from a PC.

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The first part of the transfer works OK. I need to send a 'T' to start the process. Then I need to wait for a confirmation sent by the device. The device checks which slots contains EPROMs and checks their type which takes about 5 seconds. After that I receive either a SOH (0x01) indicating all is well, or a CAN indicating there is some error. That all works.

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After that I should start sending Intel HEX records one by one; after each record I should receive either a NAK or an ACK. This part, however, never works… The device always remains with “RECEIVE” on its display and that is the end of things.

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So, next step: logic analyzer

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The logic analyzer

I connected my 16702A to the EPROM so that I could read what the device was doing. As an initial test I measured what the thing did when it was at RECEIVING and not doing anything else anymore. The LA display showed this:

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Whatever I do it always does this sadly enough:

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To be continued Next try is to ensure that the data on the 8243 port 7 is correct:

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That really is what I’m sending right now; zero after zero, and still the bloody thing does not see them 8-(