Request for GPIO Examples

punit vara punitvara at gmail.com
Thu Mar 24 07:09:27 UTC 2016


Thank you Ketul and Worth Burruss that would be really useful for
testing. I am adding these suggestion to my proposal
https://goo.gl/cGCXbS. Any other suggestions are welcome. :-)

On Thu, Mar 24, 2016 at 10:54 AM, Ketul Shah <ketulshah1993 at gmail.com> wrote:
> Hi Punit,
>
> Apart from what Worth Burruss suggested,
>
> First of all setting on off timing and testing on LED would be OK for
> primary testing.
>
> You can always test your PWM signals on DSO/CRO to have a clear picture of
> what is happening over signals.
>
> And if you can manage to have second BBB you can test signals on it too:-
> http://hackaday.com/2015/02/19/turn-your-beagleboneblack-in-to-a-14-channel-100msps-logic-analyzer/
>
> Also thinking towards a bit application side,
>
> Using PWM signals you can very DC motor speed using motor driver IC.
> RGB Led would be a great visual to test it and many more....
>
> Hope this helps for your further testing...
>
> Ketul
>
> On 23 March 2016 at 19:51, Worth Burruss <worth at motioncontrol.org> wrote:
>>
>> On 23 Mar 2016 at 0:57, punit vara wrote:
>>
>> > Hi Worth Burruss,
>> >
>> > This year I proposed a plan (https://goo.gl/cGCXbS) to develop Beagle
>> > bone black BSP which includes PWM drivers as well as I2C driver. Could
>> > you please suggest me testing methods to test PWM on BBB ?
>> >
>> > Regards,
>> > Punit
>> >
>>
>> Punit,
>>
>> I will preface this with my solutions tend to be overly complex and I do
>> not know specifically
>> what is available to use to test with in the BBB.  So this may not be what
>> you are looking for.
>> It also depends on the frequency of your PWM signals.
>>
>> When I think of test on hardware, I want to know it is working the way I
>> think it is working
>> (proving correctness).  For PWM, this means the duty cycle is correct.  I
>> would be using
>> another hardware counter timer to measure the High time followed by the
>> Low time and doing
>> the math to prove that the times are correct for the programmed duty
>> cycle.
>>
>> As an alternate, with appropriate selection of PWM frequency and software
>> timers, you can
>> do the High and low counting using the timers.
>>
>> As for me, I would find it hard to see the change in an LED's intensity
>> except in a crude
>> fashion, so would not meet my personal goal of proving correctness.   But
>> you may be
>> thinking of ON and OFF times in seconds, In which case an LED and maybe a
>> stop watch
>> would be appropriate.
>>
>> Hopefully this gives you some ideas.
>>
>> Thank you,
>>
>> Worth Burruss
>>
>>
>>
>>
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>
>


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