When I was looking at servo's, I tried with PWM but I could not get
PWM to slow down enouf.

Is there any way to slow down PWM without changing the crystal speed
to something lower then 20mhz?

Matt.

On Jan 22, 3:28 pm, Sebastien Lelong <[email protected]>
wrote:
> > You obviously haven't tried it. If there is no load at the servo
> > (e.g., when it is used to aim a sharp sensor), you can hear each
> > irregular pulse. It moves slightly off and then corrects again. But
> > when there is load on the servo, it moves away more (and takes more
> > time to correct).
>
> I'll add all servos are rather unique, interrupted pulse may not have the
> same impact.
>
>
>
> > I did numerous implementations of servo control and the reason I did
> > not get to writin a lib yet is because it is pretty time-consuming to
> > do it right. And IMHO it is not worthy to jallib to release a clumsy
> > lib. But maybe my standards are too high and adds this library value
> > to jallib, even if it does work properly when interrupts are used...
>
> If this is that time-consuming to reproduce PWM outputs in software, we
> should use a dedicated chip (I'm back on this, no surrender Joep). Few
> months ago, I found the following links:
>
>   - IC to control LEDs with PWM. May be used for 
> PWMhttp://www.maxim-ic.com/quick_view2.cfm/qv_pk/4539
>   - another IC for LEDs control, this one has been used in Arduino project
> IIRC:http://focus.ti.com/docs/prod/folders/print/tlc5940.html
>    - some thoughts about PWM software 
> implementation:http://letsmakerobots.com/node/6282
>    - Microchip AN about PWM software impl. for LEDs, 
> too:http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeI...
>
> As a reminder, "servo controller" topic on 
> jallib:http://groups.google.com/group/jallib/browse_thread/thread/53603e9bf0...
>
> > > On Jan 22, 1:46 pm, Sebastien Lelong <[email protected]>
> > > As far as I'm concerned, I have not much problem with PIC being dedicated
> > to
> > > moving servos, without being able to do other things. I see this as part
> > of
> > > a servo controller board (even shield, for jaluino), with a dedicated PIC
> > on
> > > it.
>
> > It is not about a board dedicated to move servo's. It is about a board
> > dedicated to moving *one* servo.
>
> Yes, of course. I mentioned 8 servos for one PIC.
>
> > And what is the value of board that can controle a servo, but has
> > (hardly) any ability to receive information on the desired setpoint of
> > this library?
>
> > IMO a proper library should enable an application (servo controller)
> > that support multiple servo's and communication (i2c, serial) at the
> > same time.
>
> Sure !
>
> Cheers,
> Seb

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