#!/usr/bin/env bash
# eg. bash generic-wave-pigpio.sh 25 3000 10
#
# Creates 3kHz 10% duty cycle on GPIO 25
# 3kHz 10% duty cycle -> 30microseconds on, 300 microseconds off

# If accuracy problems, /boot/config.txt dtparam=audio=off

#set -x

G="$1"
freq="$2"
duty="$3"

usage() {
  echo "$0 GPIO freq duty"
  exit 1
}

[ $G ] || usage
[ $freq ] || usage
[ $duty ] || usage


period=$(python -c "print(1000000/$freq)")
on=$(python -c "print(int($period *$duty/100.0))")
off=$((period - on))

pigs m $G w
pigs wvag $((1<<$G)) 0 $on 0 $(( 1<<$G)) $off
wid=$(pigs  wvcre)
pigs wvtxr $wid
# stop waveform by running:
#   pigs wvhlt