Monitoring RPI3 serial console

What are the correct settings on an RPI3 to watch the serial console using
a pl2303TA usb-serial cable? In this case, the monitoring window is on the
same RPI3 as the serial console being monitored.
At this point /boot/cmdline.txt contains
dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1 root=/dev/mmcblk0p2 roo
tfstype=ext4 elevator=deadline rootwait
The monitoring window is opened with
screen /dev/ttyUSB0 115200
There appears to be a login prompt, but it's mixed with a blizzard of tabs,
spaces and carriage returns, as if a local echo of some sort is causing
spurious feedback. The blizzard occurs regardless of whether any input is
typed on the screen session. It starts slowly, then speeds up. It doesn't
seem possible to enter a login and password successfully.
Thanks for reading, and any guidance!
bob prohaska
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bob prohaska
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As far as I know (have read it) the serial console is a so-called "soft" one* only ment for low speeds**, with only minimal handshake line suport.
the hardware one has, by default, been assigned to bluetooth - but you can configure it to be assigned to the serial console
**as it uses the processor speed, and that changes because of power management
Try lowering the speed to 9600 baud and see if it will work.
Regards, Rudy Wieser
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Alas, it not only doesn't work, it seems to cause worse problems. Setting the console to 9600 baud makes no discernible difference in the blizzard of (mostly) carriage returns, but it seems to cause lockup a couple minutes after the screen session is opened. Had to pull the plug to get the machine unstuck.
I'm tempted to think this is a tty configuration error, but whether it's at the screen session end or the console session end isn't obvious. When I type stty -a /dev/console the reply is: bob@raspberrypi:~ $ stty -a /dev/console stty: when specifying an output style, modes may not be set
The man page implies -a should return settings for the device.
Thanks for your attention!
bob prohaska
Reply to
bob prohaska
The connection for the serial consol (/dev/AMA???? I forgott, it's 2 years I havn't touched a Raspaberry) the setting can be modified in /boot/cmdline by defauilt it's set at 115200 bps I tinks 8 bits no parity 2 stop bits but try it!! Andre
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