Subject:
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Re: Question re hc374 Digital Out Solution
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 28 Jan 1998 15:46:51 GMT
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Original-From:
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Stephen Michael <{stephen.michael@mci.com}AvoidSpam{}>
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Reply-To:
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stephen.michael@mci.SAYNOTOSPAMcom
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Viewed:
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1983 times
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Then if Y0, Y2, and Y4 were all used for this purpose, I assume
24 digital outputs could be realized? Cool.
Thanks for the response, I'll give it a try.
Stephen
Thomas Hauri wrote:
> Hi Stephen
>
> > * outs. Connect the ’hc374’s clock line to any of the three unused
> > output latch
> > * selects of the ’hc138 (Y0, Y2,or Y4). All of these signals are present
> > on the
> > * Expansion Bus.
> >
> > Has anyone done this? Does this mean that, to get the additional 8
> > digital outs,
>
> YES :))))
>
> >
>
> > an 'hc374 should be connected as follows:
> >
> > 1. Pins 1D through 8D of 'hc374 connected to the HandyBoard's D0 through
> > D7?
> > 2. Pins 1Q through 8Q are now the digital outs?
>
> YES
>
> > Is it really this simple? Should resistors or diodes be added to the
> > circuit? How
> > are the new outputs selected?
>
> You also need to connect pin 11 (clk) to either Y0,Y2 or Y4 on the expansion
> header.The now select your new outputs. And tie pin 1 to ground to select
> the '374
>
> Now you can write to the outputs as follows:
>
> poke(0xOOOO,value);
>
> the OOOO stands for the adress (Y0,Y2 or Y4) and the value is the one you
> want on your output.
>
> Unfortunately I don't remember what address the selectors (Y0,Y2,Y4) have.
> Please ask Fred or the send a question to the mailing list.
>
> cya Tom
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Message is in Reply To:
 | | Question re hc374 Digital Out Solution
|
| I have already used the four digital outs on the SPI header and I need more digital outputs from my HandyBoard. These questions may show that I'm a neophyte as a hardware hacker, but I could use some help. In the HandyBoard FAQ under the question: (...) (27 years ago, 27-Jan-98, to lugnet.robotics.handyboard)
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