Using UART

[neilman]

Hi Everyone,

Just wonder if there's any guide on how to read the console via UART?

I've done everything written in the wiki:

1. Bought the USB to DB9 cable.
2. Soldered a 3.5mm audio jack to it (pin 2 - to the tip, pin 3 - to the ring, pin 5 - to the sleeve).
3. Switched the UART toogle on.
4. Plugged everything in.
5. Ran screen /dev/ttyUSB0 1500000.
6. Powered on the PBP.
7. Saw nothing.

Am I missing anything here?

I'm not certain but I think you are supposed to use a USB to Serial (TTL = 5v max) adapter i.e. not a true RS232 voltage adapter (one that produces positive and negative data voltages). An adapter originally with a DB9 connector will have true RS232 voltages on it (5/9/12 whatever - but NOT TTL).

Did you also note that by default the headphone jack is switched to Audio and needs to be toggled into "console" mode by opening the case and flicking the switch?
Edit: Oops - sorry - you did say you'd found the switch.

Thank you.

I'm using Prolific PL2303. Is the cable type that PBP needs documented anywhere? How would people know?

There is a suitable USB to 3.5mm jack "console" cable available in the Pine Store though I believe others have made their own cables.
The only information available on the Wiki is the connection as you've found - nothing about its "insides".
Yes some more documentation would be good.


I have the console cable myself, bought for the original PineBook, but I have not attempted to open my PineBook Pro to find and toggle that switch yet.

I measured the voltages on the plug which in my case was actually a tip-ring1-ring2-sleeve (4-connection) plug and at quiescent I was getting 5v on tip and ring1 with respect to ring2.