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HP Forum Archive 13

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MLDL2000 update: bad news and good news
Message #1 Posted by Meindert Kuipers on 8 July 2003, 1:46 p.m.

A quick update:

The bad news is that there was a fundamental mistake in my MLDL design. The good news is that I fully understand it and allows me to do a redesign of the state machine which will make the MLDL less sensible for metastability and easier to update future enhancements.

For those who are interested: I could not get the WROM instruction to work properly. It seemed to work sometimes, depending on the program that I used for initiating the WROM. After hooking up a logic state analyzer to the prototype the fault was quickly determined. I assumed that the HP41 cycle first transmitted the contents of the C-register, and then the instruction to be executed. In case of the WROM instruction, the C-register contains address and data for the WROM to operate on. This assumption was wrong, the C-register is sent AFTER the instruction.

I am currently redesigning the state machine and will hopefully be able to rebuild and test the prototype during the weekend.

Meindert

      
Re: MLDL2000 update: bad news and good news
Message #2 Posted by Vieira, Luiz C. (Brazil) on 8 July 2003, 9:24 p.m.,
in response to message #1 by Meindert Kuipers

I'm amused...

Meindert, I read your reports and I feel stuck in my inability to go so far.

Congrats. I wish I can read what you wrote and cooperate with it.

Best regards.

Luiz (Brazil)


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