Subject:
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FW: expansion board schematic posted
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Sat, 8 Feb 1997 01:15:19 GMT
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Original-From:
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MSI: Sean Cunningham <sean@*spamcake*msiconsulting.com>
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Viewed:
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1486 times
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I'd agree with this option - I don't need any more inputs, but I do need
4 logical outputs
2-4 Hi-current outputs
Serial communications
1 (preferably 2) sonar connectors
I could really use that second sonar. I don't suppose there is a way
you could design two parallel sonar connectors that are toggled with one
of the digital outs? That way we wouldn't be taxing the handyboard
resources except for the digital out.
> -----Original Message-----
> From: Fred G. Martin [SMTP:fredm@media.mit.edu]
> Sent: Friday, February 07, 1997 10:49 AM
> To: Chuck McManis
> Cc: handyboard@media.mit.edu; 'Fred G. Martin'
> Subject: Re: expansion board schematic posted
>
> It is largely a space issue, not only for chips but connectors.
>
> It definitely would be feasible to remove one of the analog muxes and
> substitute an output latch in its place.
>
> Then the specs would be 8 general purpose, 4 hi impedance, 4 LEGO
> analog ins, 2 powered dig outs, 4 servo outs, and 8 CMOS dig outs.
>
> Anyone else care to vote on this option?
>
> > If there was a way to build 24
> > digital-in/digital-out/analog-in/analog-out lines (where they could be
> > pro grammed by setting a register) that would be so fantastic as to
> > make one's robotic he art weep with joy.
>
> Chuck, can you suggest the appropriate chip? Anyone?
>
> -Fred
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Message has 3 Replies:
 | | Re: FW: expansion board schematic posted
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| (...) Hmmm... why not do this? Use a 74273 and tie it to the HB's data lines and strobe it with Y0 (or Y2 or Y4)? This would create a latched output "port" at address 0x4000. Tie two of the 74273 outputs to the 'A' side of two [N]AND gates (...) (28 years ago, 7-Feb-97, to lugnet.robotics.handyboard)
| | | Re: expansion board/multiple sonar
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| It's actually a '374 or '373 for outputs. I guess you could use them for inputs too, but you're better off using a '244 for input. Or even a '574, '573, '541, these chips put inputs on one side and outputs on the other. Very convenient. Even (...) (28 years ago, 8-Feb-97, to lugnet.robotics.handyboard)
| | | Re: FW: expansion board schematic posted
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| Sean, Using two of the SPI port pins, and a MUX and DEMUX, you should be able to gang together four of the Polaroid ultrasonic sensors. See if the code below makes sense. I wrote it a while ago, when I wanted more Polaroids, but - I didn't actually (...) (28 years ago, 8-Feb-97, to lugnet.robotics.handyboard)
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