#!/usr/bin/tclsh8.4

if {[llength $argv] != 1} { error "need serial port arg" }

set port [lindex $argv 0]

set port_stty [exec stty -F $port -g]
set term_stty [exec stty -g]

proc onreadp {} {
    global p
    while 1 {
	set c [read $p 1]
	
}

proc onreadk {} {
}

set e [catch {
    exec stty          min 0 time 0 -istrip -ocrnl -onlcr -onocr -opost \
	               -ctlecho -echo -echoe -echok -echonl -iexten -isig
    exec stty -F $port min 0 time 0 -istrip -ocrnl -onlcr -onocr -opost \
	               -ctlecho -echo -echoe -echok -echonl -iexten -isig \
	    9600 clocal cread -crtscts -hup -parenb cs8 -cstopb \
	    -ixoff bs0 cr0 ff0 nl0 -ofill -olcuc -onlcr
    set p [open $port {RDWR|NONBLOCK} 0]
    fconfigure $p -blocking false -buffering none
    fconfigure stdin -blocking false -buffering none

    fileevent stdin readable onreadk
    fileevent $p readable onreadp
}]

fconfigure stdin -blocking true
exec stty $term_stty
exec stty -F $port $port_stty