[TV] [http://82.170.247.158/Wiki/xilledson.jpg] I've been working with a Xilinx Spartan-3 demo board[http://www.xilinx.com/products/spartan3/s3boards.htm], for which there is a clock example that can be burned in the config FLASH with little effort, and that clock can be set (and some other things) over an RS-232 link. This tcl script programs the computer clock automatically into the board with a readable command: ====== #open serial port set fh [open COM1: RDWR] fconfigure $fh -blocking 0 -mode 9600,n,8,1 -translation binary -translation cr -buffering none # make a text window for incoming communication text .t -width 40 -height 10 pack .t -expand y -fill both fileevent $fh readable {.t insert end [read $fh] ;.t see end} # print time, and set the xilinx time puts [clock format [clock seconds] -format "%H:%M:%S"] puts $fh "time" ; flush $fh puts $fh "time [clock format [clock seconds] -format \"%H:%M:%S\"]" ; flush $fh ====== To put all the leds on or off from tcl connected over the serial port: ====== proc s a {global fh; puts $fh $a ; flush $fh} for {set i 0} {$i <=7} {incr i} {s "led$i on" ; after 1; update} for {set i 0} {$i <=7} {incr i} {s "led$i off"; after 1; update} ====== [http://82.170.247.158/Wiki/xilledsoff.jpg] ---- I've made a script which runs in a tclsh to communicate with theboard over the serial link, this runs also in a remote x window, the above troubles I didn't check out (timing, flow control), but it runs ok. set fh [open COM1: RDWR] fconfigure $fh -blocking 0 -mode 9600,n,8,1 -translation binary -translation cr -buffering full fileevent $fh readable {set v [read $fh] ;} clock format [clock seconds] -format "%H:%M:%S" puts $fh "time" ; flush $fh after 1000 {puts $fh "time" ; flush $fh} fileevent stdin readable { puts $fh [gets stdin]; flush $fh; } while {1} { vwait v flush $fh after 100 puts -nonewline $v flush stdout } Example: tclsh setclock.tcl KCPSM3>time 13:17:20 KCPSM3>led led LED0 OFF LED1 OFF LED2 OFF LED3 OFF LED4 OFF LED5 OFF LED6 OFF LED7 OFF KCPSM3>led0 on led0 on KCPSM3> <> Example | Device Control