Difference between revisions of "Talk:Serial debugging:Cable schematics"

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(Created page with "== getty on the serial line == It can be useful to have a tty on the serial line, e.g. if USB networking doesn't work and you still want to access the shell on a running syst...")
 
(Comment on cable for the Pixel 4a)
 
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[[User:Z3ntu|Z3ntu]] ([[User talk:Z3ntu|talk]]) 14:23, 7 October 2018 (EDT)
 
[[User:Z3ntu|Z3ntu]] ([[User talk:Z3ntu|talk]]) 14:23, 7 October 2018 (EDT)
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== Pixel 4a advice is probably wrong ==
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The text says that the headphone-jack-based cable should work for the Pixel 4a. I have such a cable, driven by an old 2.0 Bus Pirate. The cable does *not* work with my daughter's Pixel 4a, but it works fine with my old Nexus 6P. With the Pixel, nothing shows up on the terminal emulator when the boot loader starts, and an oscilloscope shows no activity on either tip or ring 1, so it's apparently not just a voltage threshold issue. I suspect that the 4a either uses a USB-based cable like the other later Pixels, or doesn't do serial at all.

Latest revision as of 01:56, 16 April 2021

getty on the serial line

It can be useful to have a tty on the serial line, e.g. if USB networking doesn't work and you still want to access the shell on a running system.

This can be achieved by enabling getty on the serial line. To achieve this, add ttyHSL0::respawn:/sbin/getty -L ttyHSL0 115200 vt100 (adjust for the serial on your device) to the file /etc/inittab. When the device is finished booting you will get a login prompt on the serial line.

Welcome to postmarketOS
Kernel 3.4.0-perf on an armv7l (/dev/ttyHSL0)
fairphone-fp2 login:

TODO: Has to be integrated (and reworded) into the main page. It's currently only about hardware so this software section would have to be fitted in somewhere.

Z3ntu (talk) 14:23, 7 October 2018 (EDT)

Pixel 4a advice is probably wrong

The text says that the headphone-jack-based cable should work for the Pixel 4a. I have such a cable, driven by an old 2.0 Bus Pirate. The cable does *not* work with my daughter's Pixel 4a, but it works fine with my old Nexus 6P. With the Pixel, nothing shows up on the terminal emulator when the boot loader starts, and an oscilloscope shows no activity on either tip or ring 1, so it's apparently not just a voltage threshold issue. I suspect that the 4a either uses a USB-based cable like the other later Pixels, or doesn't do serial at all.