Using PWM tutorial fails to compile for Raspberry Pi Pico device

[awonak]

I am following the tutorial using a Raspberry Pi Pico device. I am able to get the Blinking LED example to work, however the Using PWM tutorial fails to compile with the following error:

$ tinygo flash -target=pico
# pwm-blinky
main.go:12:22: NewPWM not declared by package machine

If I alter the sample code as shown below, I am able to successfully compile the script and get the PWM working as expected on the Pico.

// pwm, err := machine.NewPWM(pin)
// if err != nil {
// 	println(err.Error())
// }
pwm := machine.PWM4

It seems that the current implementation (src) is missing the NewPWM function and instead has a similar looking function PWMPeripheral, but that returns the slice index of the PWM group, not a pointer to the initialized peripheral.

Perhaps a solutions could be to include the NewPWM function like this:

// NewPWM calls PWMPeripheral to get the RP2040 PWM peripheral slice number that
// corresponds to the package's PWM0 throughout PWM7 handler.
func NewPWM(pin Pin) (pwm *pwmGroup, err error) {
	sliceNum, err := PWMPeripheral(pin)
	if err != nil {
		return nil, err
	}
	return getPWMGroup(sliceNum)
}

[soypat]

It seems the tinygo site is outdated, as all NewPWM API has been removed as of the PWM interface refactor. I believe @aykevl was working on creating a better PWM page on tinygo.org to better reflect these changes.

Technical details aside, I agree we are missing some sort of API to get the underlying PWM peripheral from a pin. Right now it is quite unwieldy to do this user-side. I'm unsure why this was removed in the first place and whether it would be OK to add it as you have shown or some other way.

[deadprogram]

The tutorial was updated some time ago, so now closing. Thanks everyone!