Subject:
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Re: Debugging the memory circuit
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 15 Sep 1999 03:27:30 GMT
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Viewed:
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837 times
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Hi Ed -- it *could* be that the desktop you're using isn't set up right to
download to the HB's. do you have a known good HB you can use to test the
download? alternately, there are some serial line debug instructions at
http://el.www.media.mit.edu/projects/handy-board/faq/winindex.html
fred
In lugnet.robotics.handyboard, handyboard@media.mit.edu (Edward Delaney)
writes:
> We've assembled two handy boards up to the point where we are testing
> the downloader. In section 6.0.6 of the assembly guide, it says
> "If the download process appears to go correctly, but then the Handy Board • does not boot
> with the Interactive C prompt, the memory circuit may not be working properly. • Check
> the orientations of chips U2 (the memory chip itself), U3 (the 74HC373 chip • underneath
> the memory), and U7 (the 74HC132 chip). If any of the chips is getting hot, it • is probably
> plugged in backward.
> Check the soldering joints on the above mentioned chips, re-heating any that • appear
> suspect.
> Finally, check continuity for each of the wires in the memory circuit • (including address
> lines, data lines, and select lines). Check that any adjacent wires are not • shorted together."
>
> Well, this is where we are. Both boards behave the same way and have been • assembled
> step by step by two groups of students. The download proceeds but the
> boards won't boot. No chips are hot, everything is oriented correctly.
> We've swapped chips with known good HB's to no avail.
>
> Can someone help us by being more specific about testing the memory circuit?
> There are several sets of conenctions that appear to be shorted together, but
> the soldering looks very clean and there is no visible problem. Should there
> in fact be continuity between any adjacent pins on these chips?
>
> Many thanks!
> Ed Delaney
> -----------------------------------------------------------------
> Ed Delaney edelaney@sctcorp.com (work)
> or edwardd@earlham.edu (everthing else)
> http://www.earlham.ed
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Message is in Reply To:
 | | Debugging the memory circuit
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| We've assembled two handy boards up to the point where we are testing the downloader. In section 6.0.6 of the assembly guide, it says "If the download process appears to go correctly, but then the Handy Board does not boot with the Interactive C (...) (25 years ago, 12-Sep-99, to lugnet.robotics.handyboard)
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