Peter C. Wallace wrote:
> On Mon, 22 Sep 2008, Sebastian Kuzminsky wrote:
>> Eric H. Johnson wrote:
>>> I realize that a voltmeter may not be a reliable means of measuring a PWM,
>>> but my particular voltmeter does seem to agree with the power output of the
>>> laser. It also agrees with the voltages I read when using the standard m5i20
>>> driver, which is already known to produce good values.
>>>
>>> Thus, given the consistency and linearity of the readings, I am fairly
>>> confident that they reasonably reflect what is going on with the PWM output.
>> Peter, do you have any input on this? I think an oscilloscope trace of
>> the PWM pin being driven by the hostmot2 driver is needed to move
>> forward on this issue.
>>
>
> SVST8_4.BIT (2/01/08)
>
> MD5 (SVST8_4.BIT) = dcf2cabf2a4b3fc08d8b783bbaaddeab
This is the same md5sum as the mesa-hostmot2/firmware/5i20/SVST8_4.BIT
in our CVS tree.
> Heres my little test batch file:
>
>
> wpo 1100 00fc0fc0 ; enable outputs
> wpo 1200 00fc0fc0 ; select alternate sources
> wpo 4200 ffff ; PWM rate max
> wpo 4400 ffff : turn on enables
>
> wpo 4100 20 ; 9 bit pwm mode
> wpo 4000 01000000 ; 1/2 way up = 256
> pause
> ok = 50% duty cycle at 195.31 KHz
>
> wpo 4100 21 ; 10 bit PWM mode
> wpo 4000 02000000 ; 1/2 way up = 512
> pause
> ok = 50% duty cycle at 97.66 KHz
>
> wpo 4100 22 ; 11 bit PWM mode
> wpo 4000 04000000 ; 1/2 way up = 1024
> pause
> ok = 50% duty cycle at 48.83 Khz
>
> wpo 4100 23 ; 12 bit PWM mode
> wpo 4000 08000000 ; 1/2 way up = 2048
> pause
> ok = 50% duty cycle at 24.41 Khz
>
>
> All looks to be OK
Great to hear.
Peter's test does raw I/O with the 5i20 to cause it to output the PWM
signal, so there's still a possibility that the hostmot2 driver does a
different pattern of I/O which results in an incorrect waveform output.
I've found a scope I can borrow, I'll do a similar test using the
hostmot2 driver tonight or another night later this week.
Does anyone know what the PWM frequency of the old m5i20 driver is?
--
Sebastian Kuzminsky
Theo: "Julian? I haven't seen you in twenty years. You look good.
The picture the police have of you doesn't do you justice."
Julian: "What do the police know about justice?"
-------------------------------------------------------------------------
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
