Timer PWM cannot compile when initializing multiple pins/channels on different ports.

[hacknus]

I am working on an STM32F405. The following code configuring PB1 works:

    let mut tim3_pwm = timer::Timer::new(dp.TIM3, &clocks).pwm_hz(
                                          gpiob.pb1.into_alternate()
                                      , 2000.Hz());

so does configuring PC6:

    let mut tim3_pwm = timer::Timer::new(dp.TIM3, &clocks).pwm_hz(
                                          gpioc.pc6.into_alternate()
                                      , 2000.Hz());

and PC7:

    let mut tim3_pwm = timer::Timer::new(dp.TIM3, &clocks).pwm_hz(
                                          gpioc.pc7.into_alternate()
                                      , 2000.Hz());

and PC6 and PC7 together:

    let mut tim3_pwm = timer::Timer::new(dp.TIM3, &clocks).pwm_hz((
                                          gpioc.pc6.into_alternate(),
                                          gpioc.pc7.into_alternate()
                                      ), 2000.Hz());

however, when using multiple ports (GPIOB and GPIOC) it cannot compile:

    let mut tim3_pwm = timer::Timer::new(dp.TIM3, &clocks).pwm_hz((
                                          gpiob.pb1.into_alternate(),
                                          gpioc.pc6.into_alternate(),
                                          gpioc.pc7.into_alternate()
                                      ), 2000.Hz());

with the error:

60  |       let mut tim3_pwm = timer::Timer::new(dp.TIM3, &clocks).pwm_hz((
    |  ____________________________________________________________------_^
    | |                                                            |
    | |                                                            required by a bound introduced by this call
61  | |                                           gpiob.pb1.into_alternate(),
62  | |                                           gpioc.pc6.into_alternate(),
63  | |                                           gpioc.pc7.into_alternate()
64  | |                                       ), 2000.Hz());
    | |_______________________________________^ the trait `stm32f4xx_hal::timer::Pins<stm32f4xx_hal::pac::TIM3, _>` is not implemented for `(stm32f4xx_hal::gpio::Pin<'B', 1, stm32f4xx_hal::gpio::Alternate<_>>, stm32f4xx_hal::gpio::Pin<'C', 6, stm32f4xx_hal::gpio::Alternate<_>>, stm32f4xx_hal::gpio::Pin<'C', 7, stm32f4xx_hal::gpio::Alternate<_>>)`
    |
    = help: the following other types implement trait `stm32f4xx_hal::timer::Pins<TIM, P>`:
              <(P1, P2) as stm32f4xx_hal::timer::Pins<TIM, (Ch<0>, Ch<1>)>>
              <(P1, P2, P3) as stm32f4xx_hal::timer::Pins<TIM, (Ch<0>, Ch<1>, Ch<2>)>>
              <(P1, P2, P3, P4) as stm32f4xx_hal::timer::Pins<TIM, (Ch<0>, Ch<1>, Ch<2>, Ch<3>)>>
              <(P1, P2, P4) as stm32f4xx_hal::timer::Pins<TIM, (Ch<0>, Ch<1>, Ch<3>)>>
              <(P1, P3) as stm32f4xx_hal::timer::Pins<TIM, (Ch<0>, Ch<2>)>>
              <(P1, P3, P4) as stm32f4xx_hal::timer::Pins<TIM, (Ch<0>, Ch<2>, Ch<3>)>>
              <(P1, P4) as stm32f4xx_hal::timer::Pins<TIM, (Ch<0>, Ch<3>)>>
              <(P2, P3) as stm32f4xx_hal::timer::Pins<TIM, (Ch<1>, Ch<2>)>>
            and 3 others
note: required by a bound in `pwm::<impl Timer<TIM>>::pwm_hz`
   --> /Users/linus/.cargo/git/checkouts/stm32f4xx-hal-fe8350cc04cacf3f/15134d7/src/timer/pwm.rs:232:15
    |
232 |         PINS: Pins<TIM, P>,
    |               ^^^^^^^^^^^^ required by this bound in `pwm::<impl Timer<TIM>>::pwm_hz`

The same error occurs for a slightly different syntax:

    let mut tim3_pwm = dp.TIM3.pwm_hz((
                                          gpiob.pb1.into_alternate(),
                                          gpioc.pc6.into_alternate(),
                                          gpioc.pc7.into_alternate()
                                      ), 2000.Hz(), &clocks);

[Zgarbul Andrey]

(PC6, PC7, PB1) order should work.

You are right. Pwm part of hal needs deep rework. Especially initialization. Possibly with builder pattern.
But it requires much time I don't have.

[hacknus]

Yes, that works, thank you!
And in general, thanks so much for your contribution, I am really enjoying working with the stm32f4xx-hal crate!

[Zgarbul Andrey]

What reason you prefer PwmHz over Pwm?

[hacknus]

it's what I found in stm32f4xx-hal/examples pwm.rs and a buzzer example.