pwm

#!/bin/bash

### Functions
function set_pwm () {
    if [[ $# == 0 ]]; then
	return
    fi

    PWM=$1
    # Sanity checks
    if ! [[ $PWM =~ ^-?[0-9]+(\.[0-9]+)?$ ]]; then
	echo "PWM value not a number; ignored" 1>&2
	return
    fi
    MILLIPWM=`bc <<< "scale=0; $PWM * 1000 / 1"`
    if (( MILLIPWM > 100000
          || MILLIPWM < 0 )); then
	echo "PWM value out of range; ignored." 1>&2
	return
    fi

    PWMR=`bc <<< "scale=2; $PWM * 256 / 100"`
    PWMR=`printf "%.0f" $PWMR` # Rounds here.
    PWMR=`printf "0x%02x" $PWMR` # Hex here (for show).
    if (( PWMR > 0xff )); then
       PWMR=0xff
    fi

    ./set 0x50 $PWMR
    return
}


function get_pwm () {
    PWMV=`./get 0x51`

    if (( PWMV == 0xff )); then
	PWM="100.00"
    else
	PWM=`bc <<< "scale=2; $(( PWMV )) * 100 / 256"`
    fi
    echo -e "PWM:\t$PWM\t%"
    return
}

### Main flow
# Set value if requested
set_pwm $1
# Read current value
get_pwm