I modifed my servo lib, it now uses ISR and can run up to 8 servo's. It sends 1 pulse every 4ms.
I did test sending data via serial port at 115200 baud rate which did work perfect while 8 servos where running. I still have not tested what will happen if I send it I2C commands which cause interupts. What I2C sample should I use to test this? Please take a look. Matt. On Jan 25, 12:38 pm, Sebastien Lelong <[email protected]> wrote: > I'd say with pre/post scalers. With pwm_hardware libs, I can produce a 440Hz > (A3 note, see tutorials), that's a pulse each ~2ms, near servo expectations > I think > > Cheers, > Seb > > 2010/1/25 mattschinkel <[email protected]> > > > > > > > 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 > > > -- > > You received this message because you are subscribed to the Google Groups > > "jallib" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]<jallib%[email protected]> > > . > > For more options, visit this group at > >http://groups.google.com/group/jallib?hl=en. > > -- > Sébastien Lelonghttp://www.sirloon.nethttp://sirbot.org- Hide quoted text - > > - Show quoted text - -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
