Subject:
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Re: trouble with memory
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Thu, 11 Dec 1997 03:27:29 GMT
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Original-From:
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Fred G. Martin <FREDM@MEDIAsaynotospam.MIT.EDU>
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Viewed:
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604 times
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well, the dim flashing of either yellow charge LEDs should not worry
you. all this means is that the Handy Board is drawing some power.
if you have the wall adapter plugged into the Interface/Charger board,
simply switch it to "Zap" mode.
now, onto your problem. it is possible that there is some faulty
wiring between the 6811, the 'hc373, the 'hc132, and the memory.
get the main CPU schematic, at:
http://el.www.media.mit.edu/groups/el/projects/handy-board/schemv12/cpu.html
for each wire that connects these chips, verify that there is indeed a
connection.
also, measure the resistance between +5 and each pin on the RAM, and
gnd and each pin on the RAM. except for the pins that are show as
wired to either +5 or gnd (only a few), there should not be any
connection.
this can be tedious, but it is the only way to find board level
problems.
from your debugging info, it appears that serial communications with
the host computer is not the problem.
fred
In your message you said:
> Dear Fred Martin,
> I'm in deep deeeep trouble!
> A few weeks ago I first read about your handyboard and was very excited
> about it, because I was looking for a controller board for my autonomous
> vacuum cleaner.
> So I ordered the PCB from Douglas Electronics and bought all elements to
> get started, which is difficult in Germany, because some elements were
> really hard to get. Finally I started assembling the board using Fred
> Martin's assembly instruction book. I stuck to the text very carefully,
> because I didn't want to make any mistakes. And then it happened:
> Everything worked out fine until I got to chapter 5, Memeory Circuitry.
> Last thing that worked out fine was the download using hbdl for windows.
> I was able to do the download of pcode_hb.s19 without memory, of course
> terminating with a memory error. But the transmission worked out fine.
> Then I did step 5.1. Fine, nothing wrong. Now step 5.2 memory addressing
> latch. I doublechecked the ic's notch before soldering.
> Step 5.3. memory chip and decoding gates, Fine!
> Next I installed the speaker and fixed the LCD display and put on the
> resistor pack. Now I dis the testing and ---
> TROUBLE! When plugged in power to the serial board and the telephone
> cable into both boards and I turned on the handyboard, the yellow charge
> LED started flashing very dim. Same thing when I plugged power directly
> into the handyboard. Now the charge LED on HB started flashing faintly.
> In bootstrap mode everything was fine, no flashing LED. Now I started
> the download with hbdl and transmission succeeded (The upper bar was
> complete, the lower one didn't even start). But then I got a memory
> error at 0x000. So I tried it some more times with the same result.
> Finally I tried dlm with DOS using -265 option: Downloading ConfigC0.s19
> to eeprom I succeeded, but then I got the message "got 08 at address
> 103f, wanted c0."
> I use an 68hc11 A-type processor.
> I checked every chip. They are put in in the right direction. Then I got
> another RAM chip. Same result: Memory error. When I bent away leg 20,
> /E, the flickering stopped. I checked my board thoroughly and now I am
> really stuck. Do you have a clue where the memory error might come from?
> Please help me, you are the only one to keep me from going crazy ;)
> --
> Alf H. Kuchenbuch
> Walchenseeplatz 5
> 81539 Muenchen
> Germany
> Tel. +49-89-6929026
> Fax +49-89-6929026
> (for fax pls. call in advance)
>
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Message is in Reply To:
 | | trouble with memory
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| Dear Fred Martin, I'm in deep deeeep trouble! A few weeks ago I first read about your handyboard and was very excited about it, because I was looking for a controller board for my autonomous vacuum cleaner. So I ordered the PCB from Douglas (...) (27 years ago, 11-Dec-97, to lugnet.robotics.handyboard)
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