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.
stty -F /dev/ttyUSB0
Started by ●January 6, 2020
Reply by ●January 6, 20202020-01-06
Oh, and scoping the output shows that the actual rate is at least 1MBaud (the narrowest pulses are around 1uS wide.)
Reply by ●January 6, 20202020-01-06
On 01/06/2020 01:33 PM, Johann Klammer wrote:> 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)
Reply by ●January 7, 20202020-01-07
On 01/06/2020 02:13 PM, Johann Klammer wrote:> $ 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..
Reply by ●January 7, 20202020-01-07