Serial wrap test using bash

And now, for something entirely different...

Doing a simple wrap test on a serial port should be a no-brainer in bash, but I could not find all the pieces in one place, so I assembled the pieces into a short bash script. This is not very stressful and, I am sure, could be improved, but it gets the basic job done: send a string, verify it wrapped and was received correctly, rinse and repeat.

Tip: View page source to get a better formatted copy.

#!/bin/bash # # Serial wrap test # PORT=$1 LOOPS=0 TIMEOUTS=0 MISCOMPARES=0 # Receive the wrapped string # \param $1 - port device # \param $2 - length of string that we should receive # # It works without knowing the length, but knowing the length # helps re-synchronize. # function receive { unset recv read -n $2 recv < $1 echo ${recv} > $3 } stty -F ${PORT} sane speed 115200 > /dev/null while [ true ] ; do send=`date +"%c %N"` receive ${PORT} ${#send} $$.tmp & sleep 0.1 # Block ourselves to let the receive run echo ${send} > ${PORT} sleep 0.5 # let the send complete if [ -f $$.tmp ] ; then recv=`cat $$.tmp` rm $$.tmp if [ "${send}" != "${recv}" ] ; then echo -e "\n${send} != ${recv}" let "MISCOMPARES += 1" fi else let "TIMEOUTS += 1" echo -e "\nTimeout" fi let "LOOPS += 1" echo -ne "Loops ${LOOPS} Timeouts ${TIMEOUTS} Miscompares ${MISCOMPARES}\r" done