search

s-matyukevich / raspberry-pi-os

Learning operating system development using Linux kernel and Raspberry Pi
MIT License
13.16k stars 1.29k forks source link

[Lesson 1] UART sending garbage #221

Closed jeremie-dautheribes closed 3 years ago

jeremie-dautheribes commented 3 years ago

I'm trying to test the lesson 1 but I'm only getting garbage from the mini-UART (see pic below).

image

It worked once but now I keep having the same garbage output.

I'm using screen with the following command:

sudo screen /dev/ttyUSB0 115200

I've already tested my USB-to-TTL converter on Raspbian and it works.

On Raspbian I had some issues with the baudrate so I tried to compile the kernel with baudrate = 9600 (adaptating screen command) but I still have the same output.

Here is my config.txt:

enable_uart=1
arm_64bit=1
disable_commandline_tags=1

I've set arm_64bit=1 beacause I'm using a RPI 3B+ model and with kernel_old I don't have anything on the screen (even following the guide and removing all the kernel images).

jeremie-dautheribes commented 3 years ago

Ok so when removing enable_uart=1, it works, whether with 9600 or 115200 baudrate ...

I should have checked that before but I hope it will help someone 😄

thanoskoutr commented 3 years ago

Thank you very much, you saved me from spending any more hours. I have left the config.txt from the Raspbian install and never thought that would be the problem.