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+-- Forum: Pinebook (https://forum.pine64.org/forumdisplay.php?fid=76)
+--- Forum: Pinebook Hardware and Accessories (https://forum.pine64.org/forumdisplay.php?fid=80)
+--- Thread: Serial port (/showthread.php?tid=4609)
Serial port - pfeerick - 06-21-2017
Just some notes on using the 'earphone serial console' on the Pinebook.
You might have seen the reference guide in the Pinebook resources section entitled "Pinebook Earphone Serial Console Developer Guide" (click the link if you haven't seen it yet!).
You'll have then also seen the super user friendly /sys/class/sunxi_dump/write calls that enable and disable this functionality.
Well on all of ayufan's linux desktop environment builds you have the super handy pinebook_enable_uart.sh and pinebook_enable_headphones.sh scripts (you'll need sudo to run them as they're located in /usr/local/sbin - and need root privleges anyway). You can run them to easily toggle between the two different stages. This will let you see all the boot messages and interact with the serial console on your pinebook, and use the built in serial connection, which is available as /dev/ttyS0 once you boot.
One gotcha will be that on the pinebook DE (desktop environment builds) there is a pinebook-headphones service that runs during boot, so the UART is disabled part way through the boot process. You can easily change this behaviour using systemctl. Simply issue the command sudo systemctl disable pinebook-headphones at a terminal in order to disable it, and naturally you can also enable it again if you wish the headphones functionally to be automatically made available.
There is a possibility this behaviour will change in the future, and that UART via the headphones jack will only be switchable via an on-board switch, so watch this post to see if this behaviour does indeed change. This switch is already present on most production pinebooks, and is a slide switch (referred to as SW11 on p9 of the mainboard schematic) located on the edge of the main circuit board on the far right side. At the present time it simply overrides the GPIO pin that is toggled by the enable/disable scripts, and forces the UART to be permanently on.
RE: Serial port - guidol - 07-05-2017
I assume its 3.3V TTL-port? Or is it 5V?
A serial cable for Intel Galileo Gen1 has also a 3.5mm Jack
RE: Serial port - MarkHaysHarris777 - 07-05-2017
(07-05-2017, 12:38 AM)guidol Wrote: I assume its 3.3V TTL-port? Or is it 5V?
A serial cable for Intel Galileo Gen1 has also a 3.5mm Jack
The logic is 3v3 ;