stty -F /dev/ttyUSB0

Jan 06, 2020 4 Replies

stty -F /dev/ttyUSB0 speed 0 baud; line = 0; min = 1; time = 0;



-brkint -icrnl -imaxbel



-opost



-isig -icanon -iexten -echo



(something is wrong)



stty -F /dev/ttyUSB0 ispeed 38400 stty: /dev/ttyUSB0: unable to perform all requested operations



But if I give an obv wrong value it doesn't complain. stty -F /dev/ttyUSB0 ispeed 3840


The dongle is a FTDI Chip TTL-232R-5V USB to TTL Serial Cable(5.0V)-1.8m (2419945 at Farnell)



On Linux kernel Version 3.14.15



I guess since the're the monopolist they don't have to produce working hardware anymore.



And yes, I've read the crap about read write access on stackoverflow. I am in the plugdev group and it's read/writable for plugdev.



Oh, and scoping the output shows that the actual rate is at least 1MBaud (the narrowest pulses are around 1uS wide.)

ok. seems it's not the actual number that matters, but the number of invocations. It's some internal state that changes.

$ stty -F /dev/ttyUSB0 ispeed 38400 stty: /dev/ttyUSB0: unable to perform all requested operations $ stty -F /dev/ttyUSB0 ispeed 38400 (this one succeeds)

may have been a user error. $ stty -F /dev/ttyUSB0 38400 works at once.

I did scope the output again and observed a tau of 23 uS. (=baud rate err of 0.11) Is this too much? Because I still can't get the uC to respond..

Nah user error again. is closer to 25uS...

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