Hi Everyone,

I created a project which did this for the now (seemingly) defunct
Electronics Australia magazine, you can find all the details at
http://www.digitalnemesis.com/ash/projects/picservo

It is controlled via a bit banged serial connection and the servos are
serviced in an interrupt routine. However, after the recent replies, I now
know why I couldn't get full travel out of my futaba servos.. I assume 1-2ms
as the max range... interesting.. I adjusted by allowing the user to set and
"offset" then allow the servo to travel +/-45 degrees from that. It seems
that my futaba servos thought that 1-2ms = 90 degree travel, which kind of
makes sense when you look at the maximum travel you would get out of
something connected to the servo like a rudder or something.

Anyway It may give you something to work from. All the ASM code is there and
well commented, as well as the (simple) circuit and PCB artwork for the
project.

Hope that helps!
Ash.

> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Robert Shady
> Sent: Friday, 9 February 2001 2:19 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: [PIC]: PIC16F84/16F877 ISR SERVO CONTROL
>
> I've looked at a number of servo control source, and I
> haven't found anybody else doing it this way (it
> appears everyone dedicates a 16f84 to this task).  I
> figure this would have to be table driven, but just
> can't get this to work.  The timing is something else
> I'm having trouble getting just right.  Both chips are
> clock externally w/a 20mhz crystal.

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.