Pin 26 and Pin 11 are the same PWM13.1

TinyCLR
1

I have an issue with the pinout for the SCM20260E where I have wired the backlight to pin 26 to use PWM13.1 or PA6 GPIO.

When I try to select the PWM13.1 for PWM output, it only has PF8 listed for the GPIO, so on checking I find this on pin 11. Seems to be a duplicate that won’t work for PWM. :frowning:

Is the ref to PWM13.1 on pin 26 wrong?

2

Same error with the SCM20260N

I have ended up using the software version of the PWM to avoid wire links and repairs to 3 boards :slight_smile:

3

Looking at the schematics https://www.ghielectronics.com/pdf/scm20260e-rev-b-schematic.pdf

Both pins have PWM13.1

image

and

image

I would expect the firmware to automatically pick the one you have selected to use, not both. But maybe this is broken in the firmware. We will check.

Error in pinout of SCM20260E?
4

Default, only PF8 is PWM13.1. We need to remove PWM13.1 from PA6.

If you really want to use PA6 then you can use GHIElectronics.TinyCLR.Devices.Gpio.LowLevel that can bring PWM13.1 to PA6 and PF8 is GPIO.

5

This is example code to pass PF8 to PA6, tested on SC20260N


var pwm = PwmController.FromName(SC20260.Timer.Pwm.Controller13.Id);
var channel = pwm.OpenChannel(SC20260.Timer.Pwm.Controller13.PF8);

pwm.SetDesiredFrequency(1000);         
           
LowLevelController.TransferFeature(
    SC20260.GpioPin.PF8,   // source (currently owns the signal)
    SC20260.GpioPin.PA6,   // destination (customer's LED backlight)
    new Settings {
        mode          = PortMode.AlternateFunction,
        alternate     = AlternateFunction.AF9,
        type          = OutputType.PushPull,
        driveDirection = PullDirection.None,
        speed         = OutputSpeed.High,
    });

channel.SetActiveDutyCyclePercentage(0.1);
channel.Start();
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