PWM won't run in simulator

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diversedevices
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PWM won't run in simulator

Post by diversedevices »

Flowcode V8.2.0.12
PIC 16F1704

I have a very simple test of Enable the PWM and set the 8 bit Duty Cycle. I also have a 1 second test running. I am watching with the oscilloscope. The 1 second test shows on the scope. Nothing for the PWM. I have tried Channel 1,2,3,4 / Timers 2,4,6 and routing the output to various pins (currently C.3)

I have also tried with different PIC chips with no results. Full disclosure: I am new to flowcode - usually program at assembler level. My feeling is I am missing something that would be obvious to a seasoned user.

I have read other PWM threads here, but they are years old.

Thanks!
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Benj
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Re: PWM won't run in simulator

Post by Benj »

Hello,

We do try and put everything on the scope that we can however PWM is currently not supported. This is mainly because it has the ability to cause the simulator to run slowly also precise timings (sub ms) will be extremely complex to generate in the simulator and so waveforms will likely be wrong.

To get around this the wave form is instead shown on the component on the panel.

I'm in the process of releasing a document that shows exactly what does and doesn't simulate.

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Re: PWM won't run in simulator

Post by diversedevices »

Thank you for the explanation.

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Re: PWM won't run in simulator

Post by diversedevices »

I have programmed an actual chip with this code and the 1 second test output works, but nothing on the PWM.

Is there something else that needs to be done to create the output?

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Re: PWM won't run in simulator

Post by LeighM »

Try setting the period register (see properties) to a value greater than the (128) duty setting (e.g. 255)

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Re: PWM won't run in simulator

Post by diversedevices »

Thank you for the quick reply, Leigh.

I tried altering the period without success, I tested the hardware to make certain C.3 was functioning, I tried combinations of Channel 1,2,3,4 with Timers 2,4 & 6. I have tried two different chips (just in case). Compiles within FlowCode without errors.

I also just tried substituting a 16F1825 and running this, and not output on PWM. I must be missing something very basic.

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Re: UPDATE: PWM won't run in simulator

Post by diversedevices »

I saw that there are 2 PWM functions. One is in the "Creation" section and the other is in the "Output" section. I emailed Matrix and the reply was that they are the same (but you have to pay extra for the one in the Output section which is included with the Basic IO purchase).

I went ahead and purchased the BASIC IO, set up the Output PWM and it WORKS as expected. The screenshot shows the two different PWM's. The PWM1 is the Output PWM, and the cal_pwm1 is the "Creation PWM'.
PWM.jpg
PWM.jpg (12.75 KiB) Viewed 2630 times
I suspect the "Output PWM' creates a PWM using microcontroller resources and the "Creation PWM' was intended to use the PWM function in many of the PIC processors.

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