Creates two PWMs with different duty cycless using periph.io

pwm.go

package main

import (
  "log"
  "os"
  "os/signal"
  "time"

  "periph.io/x/periph"
  "periph.io/x/periph/conn/gpio"
  "periph.io/x/periph/host/bcm283x"
)

func main() {
  if _, err := periph.Init(); err != nil {
    log.Fatal(err)
  }
  c := make(chan os.Signal, 1)
  signal.Notify(c, os.Interrupt)
  defer bcm283x.GPIO12.Halt()
  defer bcm283x.GPIO13.Halt()
  const steps = 20
  t := time.NewTicker(50 * time.Millisecond)
  for i := 0; ; i++ {
    select {
    case <-c:
      return
    case <-t.C:
      j := i % (steps + 1)
      if (i/(steps+1))&1 == 1 {
        j = steps - j
      }
      v := (gpio.Duty(j) * gpio.DutyMax) / steps
      if err := bcm283x.GPIO12.PWM(v, 100*time.Microsecond); err != nil {
        log.Fatal(err)
      }
      if err := bcm283x.GPIO13.PWM(gpio.DutyMax-v, 100*time.Microsecond); err !==
 nil {
        log.Fatal(err)
      }
    }
  }
}