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serial port input control Posted by TimT (TimT), 20 September 2004 Similar to the last posting -I am setting up a serial port and sending data in a defined format to a device. The device responds in a defined format. But if the initial output format is wrong, there is no reponse or an undefined one. Using the commands in the last posting: set rsport [open /dev/ttyUSB0 w+] fconfigure $rsport -blocking 1 -buffering none .... set bytin [read $rsport 1] it would lock in the last line if no input is received and an exit button would not be able to used to exit the program. How can I check there is a input or not without having to read it? Posted by admin (Graham Ellis), 21 September 2004 The -blocking 1 option that you have specified causes the channel to block while awaiting input. If you replace it by -blocking 0 then it will not block. You will then need to check the return from the read to see if you've got the one byte requested or nothing at all.This page is a thread posted to the opentalk forum
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