Read an I2C Portexpander

read_portexpander.sh

#!/bin/bash

ADDRESS=0x27

printf "76543210 76543210\n"
while :
do
  v=$(i2cget -y 0 $ADDRESS 0x00 w)
  echo ${v: -4:4} | xxd -r -p | xxd -b | awk '{split($0,a," "); printf "%s %s\r", a[2], a[3]}'
done

Reads a 16 bit I2C portexpander like the PCF8575 and displays the result in bit representation.

$ ./read_portexpander.sh 
76543210 76543210
11111111 10011111