Getting data from UART1&UART3 with recent kernels

[aikipooh]

Good UTC night, everyone!

I have 3.13 kernel on A13-Olinuxino, I have auxiliary device, connected to PE10&PE11, which I would like to use, and another one connected to PG9&PG10. I have never worked with all this lowlevel stuff, so sorry if my questions don't make sense:)

Update: I've modified the dts, adding

Code Select Expand

uart3: serial@01c28c00 {
pinctrl-names = "default";
pinctrl-0 = <&uart3_pins>;
status = "okay";
};

where

Code Select Expand

uart3_pins: uart3@0 {
allwinner,pins = "PG9", "PG10";
allwinner,function = "uart3";
allwinner,drive = <0>;
allwinner,pull = <0>;
};


I get now the stuff the device connected to PG9&PG10 is sending.
I've also modified uart1 to use uart1_pins_a (PE10&PE11), but that doesn't help, I cannot interact with the device connected to PE10&PE11. The linux console is not spawned there, but bootloader spits some output to PG3&PG4. Could it confuse the port somehow?
And what is the difference between UART1_TX on processor pin 152 and on pin 124?

[LubOlimex]

Hey there

Make sure to use latest Debian release since it takes it possible to use UART3 for such connections. You would need to use wires to connect your device but nothing else (no need of software adjustments). The release can be downloaded from here: https://drive.google.com/file/d/0B-bAEPML8fwlLTVPbGNIclVhTDQ/edit?usp=sharing

As mentioned in the wiki article:

gpio12_pg9(GPIO2/pin10) is connected to on board LED and it is multiplexed with UART3_TX and gpio13_pg10(GPIO2/pin8) is multiplexed with UART3_RX. Therefore, if you want to use these ports like GPIO then UART3_TX and UART3_RX will not be available.

To use UART1/UEXT you need to disable the debug port.

You should edit inittab file in /etc directory.

#nano /etc/inittab

Comment
#T0:2345:respawn:/sbin/getty -L ttyS0 115200 vt100

Save and run
#init q

Remember that you would need to debug via SSH, monitor or display now on!

Best regards,
Lub/OLIMEX