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From: nahshon@dan.haifa.ibm.com (Itai Nahshon)
Subject: Re: Servo control chip/program
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In-Reply-To: 931603@edna.swin.edu.au's message of 27 Sep 1994 04:46:03 GMT
Date: Fri, 30 Sep 1994 14:30:17 GMT
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	<36882bINNr4t@edna.cc.swin.edu.au>
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In article <36882bINNr4t@edna.cc.swin.edu.au> 931603@edna.swin.edu.au (Andrew Victor Dennison) writes:

>Jean-claude LEGER (system@leto.enet.dec.com) wrote:

>: 	And what about up to 7 servos on one PIC16C84 or STAMP i/o line ?
>: 	Seems to be possible if the NE5045 is an RC like decodeur.
>: 	Does anybody have pinout and/or typical schematic for this chip ?

>Early RC receivers used a serial to parallel converter as the decoder:  I
>would suggest using this simple option as you don't need the other
>functions of the 5045.  You simple input a '1' as the first bit of data
>and then clock the chip.  The period between the clock pulses determines
>the pulse width to each servo.  You could connect 7 (maybe 8) servos to
>the parallel outputs of the S->P converter.

>This cct works by the '1' first loaded being shifted through each output,
>the time it spends at each output being determined by the clock period (as
>previously stated).

>Hope this helps...
>Andrew

I've used a 4022 (or 4017) CMOS Johnson counter about the same way.
It's connected to a 68HC11 (can be extended to hook up to 36 servos
with 4 4017 counters on a single HC11).
Look at anonymous FTP server cher.media.mit.edu, /pub/incoming/itai/* for
68HC11 assembly source (other details are commented in the source). 

Itai nahshon
Haifa, Israel
nahshon@vnet.ibm.com

 
