Subject:
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Re: 8 bits A/D bus
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 14 Jan 1998 21:59:38 GMT
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Original-From:
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Mike Vande Weghe <VANDEWEG@PARLANCE-NCSstopspam.COM>
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Viewed:
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1961 times
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I am building a somewhat similar circuit (a high-current h-bridge for
the handy board), although I only need to read the data lines. However,
the same approach will work for writing to the bus. My circuit lives on
a board which plugs in between the LCD and the main board. That is, it
has two male header strips on the bottom to plug into the CPU board, and
it has one female header strip on top to accomodate the LCD board. I
have wired the pins on the leftmost header straight through so that the
LCD can work as before. For reading the data bus, I have also attached
the D0-D7 lines to a 74HC374. The Y4 line controls the clock to this
chip, which lets me write a word to the chip by writing to address
0x6000. For writing to the HB bus, you can hang a 74HC244 on the data
lines, and run the Y5 line to the /G pins (pin numbers 1 and 19). That
will allow you to read a word from that chip by reading from 0x6000.
For examples, look at the schematics for the Handy Board's motor driver
and digital input circuits; they work the same way, using lines Y6 and
Y7, respectively.
Fred did a good job designing the Handy Board to be expandable; these
changes are relatively simple, and give you a lot of flexibility. I
can't wait to finish by own circuit and try it out.
Good luck,
Mike Vande Weghe
vandeweg@alum.mit.edu
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Message is in Reply To:
 | | 8 bits A/D bus
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| Hello, I've bought a handy board, and try to build a card to enserve two motors. On that card I have a IC chip (HP hctl 1100) that needs to be link to a 8 bits Adress/data bus in both reading and writing modes. My problem is where to pick such a bus (...) (27 years ago, 14-Jan-98, to lugnet.robotics.handyboard)
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