NanoPi Neo 2 UART (TTL) connection

[koval]

Hello,
I have NanoPi Neo 2 and I want connect my USB-TTL adapter to UART debug port.

What is logic levels for Rx&Tx? 3.3 V or 5 V ?
What speed should I tried for connection? 9600 or 115.200 ?

[koval]

I found that correct TTL is 3.3 V and speed 9600.
But when I connected, nothing printed in terminal.

Any suggestion ?

[guidol]

I found that correct TTL is 3.3 V and speed 9600.
But when I connected, nothing printed in terminal.

Any suggestion ?

the debug-port of the Neo2 has 5V and the right speed is 115.200

[koval]

I found that correct TTL is 3.3 V and speed 9600.
But when I connected, nothing printed in terminal.

Any suggestion ?

the debug-port of the Neo2 has 5V and the right speed is 115.200

Hm, very interesting. Thank you for info. I will try to check with new settigns...

[koval]

I found that correct TTL is 3.3 V and speed 9600.
But when I connected, nothing printed in terminal.

Any suggestion ?

the debug-port of the Neo2 has 5V and the right speed is 115.200

Checked with your settings and it works!
Thank you so much!

[v8dave]

The debug port provides 5V but the actual voltage levels for the RX and TX lines are 3.3V. There are current limiting protection resistors inline but best to use 3.3V levels. VCC_IO is wired to 3.3V in the schematic. The baud rate is likely why you didn't see anything.