On Tue, 23 Sep 2008, Eric H. Johnson wrote:
> Date: Tue, 23 Sep 2008 21:09:44 -0400
> From: Eric H. Johnson <[EMAIL PROTECTED]>
> Reply-To: "Enhanced Machine Controller (EMC)"
> <emc-users@lists.sourceforge.net>
> To: "'Enhanced Machine Controller (EMC)'" <emc-users@lists.sourceforge.net>
> Subject: Re: [Emc-users] stepgen & pwmgen fixes
>
> Sebastian,
>
> Can you check to see that the pwmgen.enable is working properly. I was
> running samples all day (which looked great, btw, after resolving a very odd
> problem) so I did not have a chance to do much testing. I am now dropping
> the enable when the shutter closes, however the pwmgen.value is still
> getting values. The laser was still coming on even when the enable was low.
>
> I will try setting the frequency of the pwm from the latest update and
> hopefully test that tomorrow.
>
> Regards,
> Eric
>
Well I'm not Sebastian, but I know why you are seeing that behavior:
The enable register was designed for our PWM and Analog output daughter cards
so it doesnt actually affect the PWM output, its just a group of (active low)
output bits used to enable the daughter card output channels. I can certainly
change this behavior so that the PWM output is forced low when a channel is
not enabled (cheap in terms of FPGA hardware). The active low enable output is
used to guarantee that the motor drive outputs are off at power up (or
watchdog bite)
I dont think there are any bad side effects of forcing the PWM output low if
disabled, but there are possible bad side effect of using a active high PWM
output without the enable (Laser is on high at power up unless you have some
other active low enable signal)
Peter Wallace
Mesa Electronics
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.
-------------------------------------------------------------------------
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
