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Have you visited the Allwinner Chipset wiki? - http://linux-sunxi.org/

connecting to serial port

Started by RAWX86, March 30, 2013, 10:33:51 am

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Got my Cubie for about a week now, so still new to this...

Since it does not boot from from µSD (tried Berryboot and some pre-made images - no screen on HDMI / no device on local network), I want to troubleshoot via serial connection.

I have poor pure package only. So I had to wire to RS232 myself.
There is connected:

RX > Pin 2
TX > Pin 3
GND > Pin 5

...but I cannot seem to get any messages not on Linux (using screen, like descriped at http://linux-sunxi.org/Cubieboard/TTL) nor Windows using Putty.

Am I missing something, maybe some connection that verifys the Sub-D to be plugged in or something like that?

Any suggestion appreciated...  :)


which microcontroller do you use for ttl?


March 30, 2013, 06:44:12 pm #2 Last Edit: March 30, 2013, 06:55:16 pm by RAWX86
Quote from: BigWhoop on March 30, 2013, 05:45:24 pm
which microcontroller do you use for ttl?

The device is displayed as VID_067B&PID_2303&REV_0300 / PL2303...

Maybe that chipset cannot work for TTL?
I am not realy sure if I understand corretly how this works out...  :-\



I tried to swap RX / TX - but only getting garbled *** in console...


March 31, 2013, 06:00:50 am #3 Last Edit: March 31, 2013, 09:12:03 am by RAWX86
Arg... I have been stupid / should have checked some documentation, before just trying to connect something refering to assignments diagrams...  :-[

As I may not be the only noob around here (at least I hope so), heres the explantion why you cannot use a USB / RS232 for TTL:


addition / just for fun:

Here in Germany everything is closed until tuesday (easter feasts), no one would ship anything until then, so I decided to do some modification...

I thought it should be possible to grab data signals from the UART before the MAX-232 makes it RS-232 compliant:

Datashet for PL2303HXD is avaible at http://www.prolific.com.tw/US/CustomerLogin.aspx
The connection on IC is TXD / Pin1, RXD / Pin5, GND / Pin 18, I have the GND connector soldered to a  9SD female connector, as it is a little tricky to solder to the IC with a 5mm iron...  ;D

Those converters are about 3€ only and plenty of you may have one laying around, so it is a pretty cheap solution and works like a charm, anyhow I do not recommend it as I badly hurt my finger, when removing the plastic cover with a cutter. XD

Learning never stops.  :)