Subject:
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Re: 16 digital outputs as Fred suggested
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Mon, 13 Apr 1998 12:15:34 GMT
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Original-From:
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Fred G. Martin <fredm@media.mit.edu#Spamcake#>
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Viewed:
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1569 times
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1. please read the Appendix B documentation in
http://lcs.www.media.mit.edu/groups/el/projects/handy-board/techdocs/
which explains this in more detail than the FAQ.
2. you must the even-numbered Yx signals for output latches. Since
Y6 is taken (by the on-board latch for the motor drivers), you're left
with Y0, Y2, and Y4.
3. To set the bits in a latch connected to Y0, all you do is write a
byte anywhere in the 0x4??? memory range; e.g., "poke(0x4000, 0x55)"
sets every other bit. That's all there is to it.
Fred
In your message you said:
> Hi guys,
> I needed 16 digital outputs for my handyboard, so I put up a very simple
> expansion board the way Fred suggested in his handboard FAQ: I connected
> two more hc374 with their d-inputs to LCD-display's data bus (d0 - d7).
> Then I connected the first hc374's clock to y4 and the second one's to
> y5. Really simple, indeed. Now I would like to use those outputs with
> Interactive C.
> I figured, if I want to set output 0 to 6 low and output 7 high then I
> have to put 0+0+0+0+0+0+0+2^7=128 on the bus. Then I have to pulse y4
> low
> for a short time for hc374 to put the bus word through to its Q outputs.
> In HB Technical Reference (chapter 11 Pin out Detail), Brian Schmalz
> suggests to pulse y4 low for 1 cycle by the command WRITE 0x6000
> So that's all I know.
> Now my question:
> Could you tell me the IC code to operate those outputs using IC?
> I hope, somebody out there has solved this problem before.
> Alf
> (the only German Handyboard user?)
>
>
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Message is in Reply To:
 | | 16 digital outputs as Fred suggested
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| Hi guys, I needed 16 digital outputs for my handyboard, so I put up a very simple expansion board the way Fred suggested in his handboard FAQ: I connected two more hc374 with their d-inputs to LCD-display's data bus (d0 - d7). Then I connected the (...) (27 years ago, 12-Apr-98, to lugnet.robotics.handyboard)
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