Re: Request for GPIO Examples

[punit vara]

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  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  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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Re: Request for GPIO Examples

[punit vara]

On Wed, Mar 23, 2016 at 7:51 PM, Worth Burruss  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
>
>
>
>
Did you mean to say ?  General purpose timer that is continuous
increasing can be configured to toggle the PWM output high when a
certain value reached and low when it overflows. I have referred this
from here (

Activating PWM via Timer Registers)

http://elinux.org/BeagleBoardPWM#OMAP_Mux_Configuration
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Re: Request for GPIO Examples

[Ketul Shah]

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  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
>
>
>
>
> ___
> devel mailing list
> devel@rtems.org
> http://lists.rtems.org/mailman/listinfo/devel
>
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Re: Request for GPIO Examples

[Worth Burruss]

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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Re: Request for GPIO Examples

[Worth Burruss]

On 16 Mar 2016 at 2:30, punit vara wrote:

> > Hi
> >
> > Are there any example programs for the GPIO? I realize they would be
> > specific to the BBB or Pi but would appreciate getting some code.
> >
> > Thanks.
> >
> > --joel
> I tested GPIO APIs in Beaglebone black with LED blinking. You can look
> into https://github.com/punitvara/rtems_gsoc16 if it's useful for you.


Thank you, I was the one asking. It is what I was looking for.

Sorry it took so long to respond , I have been away from email.

Worth



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Re: Request for GPIO Examples

[André Marques]

Hello Joel,

Às 18:15 de 15-03-2016, Joel Sherrill escreveu:

Hi

Are there any example programs for the GPIO? I realize they would be 
specific to the BBB or Pi but would appreciate getting some code.




I have some sample applications for the Pi that I have used to test the API:

https://github.com/asuol/RTEMS_rpi_testing/tree/master/GPIO

The BBB should also be able to use these just by changing the pin 
numbers used or the pin configuration file depending on the test.



Thanks.

--joel


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--André Marques
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Request for GPIO Examples

[Joel Sherrill]

Hi

Are there any example programs for the GPIO? I realize they would be
specific to the BBB or Pi but would appreciate getting some code.

Thanks.

--joel
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