bash/serial_loopback_test.sh

   1 #!/bin/bash
   2 #(c) Tomas Mudrunka 2022
   3
   4 [ -z "$1" ] && {
   5         echo "Usage: $0 /dev/ttyTX [/dev/ttyRX]"
   6         exit 1
   7 }
   8
   9 port_tx="${1:-/dev/ttyUSB0}"
  10 port_rx="${2:-$port_tx}"
  11
  12 testdata="${RANDOM}d82b2ae45432e7c80699852ab557b279c42180a379711aae85487bda0cc58602f65c0ab5af0d510d6ac1606c52f887f3332052f67c45212dbbf2730${RANDOM}"
  13
  14 echo "Running loopback test on $port_tx -> $port_rx"
  15
  16 stty -F "$port_tx" raw -echo
  17 stty -F "$port_rx" raw -echo
  18
  19 exec 5>"$port_tx"
  20 exec 6<"$port_rx"
  21
  22 errcnt=0
  23 while true; do
  24         echo "$testdata" >&5
  25         unset line
  26         read -rst 1 -u 6 line
  27         #echo "LINE: $line"
  28         [ "$line" != "$testdata" ] && {
  29                 ((errcnt=errcnt+1))
  30                 echo -e "$(date +'%D %T')\t$errcnt\tError receiving data $port_tx -> $port_rx"
  31         }
  32 done
  33
  34 exec 5>&-
  35 exec 6<&-