PWM on `D05` on F7Featherv2 does nothing

[ctacke]

Create an app that does this:

var pwm = Device.Pins.D05.CreatePwmPort(50.Hertz());
pwm.Start();

Scope says the line is flatlined - no pulses at all.

An ioctl is properly being sent from Core with the following: Channel: 1 Timer: 3 Duty: 32767 Frequency: 50

[Peter-Moody]

For F7FeatherV2 the F7's Timer 3, Channel 1 is shared by D05 (PB4) and D09 (PC6). PWM does work on D09. Looks like the decision was made to support D09and not D05 for PWM. Behavior Attempting to use D05 just silently doesn't work. However, attempting to use D06 throws an exception. D05 should do the same.

[patridge]

This seems to have highlighted some inconsistencies on Docs.

We have this generic-named pinout diagram (technically v1, I think) that says D05 is PWM-capable.

Then, we have two v2-specific pinout diagrams that differ based on the pinouts in that area of the board.

• docs/Common_Files/Meadow_F7v2_Micro_Pinout.svg shows NO PWM on D05 or D06.
• static/Common_Files/Meadow_F7v2_Micro_Pinout.svg shows YES to PWM on D05 and D06.

We also have mention of what I think is this same issue in the Beta6 release notes.

@Peter-Moody Trying to put together a list of docs changes needed, if you can verify. Then, based on that, we've got a lengthy to-do list on our end.

Questions:

• Is D05 NOT capable of PWM on Feather v2 but IS capable on Feather v1?
• Is D06 capable of PWM on Feather v1 or v2?
• Is D05/D06 valid for PWM on other Meadow boards? (Trying to decide what samples to change or note v2 restrictions, such as M.F.Leds.PwmLed.)

Action items for docs:

• [ ] Unify on a single, correct, Feather v2 pinout SVG, delete one and update all references to the remaining, correct one. (This can probably be done by hand-editing the SVG.)
• [ ] Clarify "v1" subject in the Feather v1 diagram, possibly just editing the title text in the raw SVG.
• [ ] Review and update various usages of the original SVG based on the surrounding text context for v1 or v2, defaulting to v2 whenever it's not specified.
• [ ] Update any Meadow.Foundation.Leds.*.md samples with a note about pin restrictions on Feather v2.
  • [ ] https://github.com/WildernessLabs/Documentation/blob/develop/docs/api/Meadow.Foundation/Meadow.Foundation.Leds.PwmLed.md?plain=1#L37-L38
  • [ ] https://github.com/WildernessLabs/Documentation/blob/develop/docs/api/Meadow.Foundation/Meadow.Foundation.Leds.LedBarGraph.md?plain=1#L37-L38
  • [ ] https://github.com/WildernessLabs/Documentation/blob/develop/docs/api/Meadow.Foundation/Meadow.Foundation.Leds.PwmLedBarGraph.md?plain=1#L37-L38
• [ ] Update chart in the Meadow_Basics/IO page to remove PWM channel for D05 and D06.
• [ ] Update PWM sample here to a pin that is more ubiquitous than D05.
• [ ] [extra credit] Update this Fritzing diagram to avoid D05/D06 use for PWM bar graph

[patridge]

Possible impact of locations from changes coming in #776.

[Peter-Moody]

What I noticed was that the F7FeatherV2 image of the board showed both D05 and D06 supported PWM. Neither one do. Our website text was correct. I think that @jorgedevs has fixed the image, but I could be wrong.

[Peter-Moody]

I have no reason to believe that there is anything wrong with the F7FeatherV1 documentation.

[jorgedevs]

@patridge D05 and D06 on the F7v1 does work. Is just that v2 they added more features, so drawback was dropping PWM capability to D05 and D06.

[patridge]

We should have everything addressed now, removing that as a PWM option everywhere we can.