Preparation
- You need a
Serial Debugging Tool
. In this guide, we will use aUSB to TTL Converter
.
Connections
Follow these steps to make the correct connections:
Connect the Tool Pins to the GPIOs, and check the Tx / Rx Pins once more to ensure that you’ve made correct connections:
- Tool Pin
GND
: <—>Pin17
of VIMs’s GPIO - Tool Pin
TXD
: <—>Pin18
of VIMs’s GPIO (Linux_Rx) - Tool Pin
RXD
: <—>Pin19
of VIMs’s GPIO (Linux_Tx) - Tool Pin
VCC
: <—>Pin20
of VIMs’s GPIO
- Tool Pin
Insert the USB-end into your PC.
The connections should look like this:
Blue color line: Tool Pin
TXD
, orange color: Tool PinRXD
, black: Tool PinGND
Another photo for more details (VCC
Pin is not necessary):
Setup Minicom Protocol
Install minicom:
1 | $ sudo apt-get install minicom |
Add Access Permission:
1 | $ sudo usermod -a -G dialout $(whoami) |
open minicom
1 | $ minicom -D /dev/ttyUSB0 -b 115200 |
-D
to designated device, -b
to designated baud rate
1 | Welcome to minicom 2.7.1 |
How to use minicom
Ctrl + a
or Ctrl + z
enter minicom control mode. Keyboard o
can enter configuration mode
1 | +-----[configuration]------+ |
Serial port setup
option use to set up serialSave setup as dfl
option use to save you configure .
Keyboard q
use for exit minicom .
1 | +----------------------+ |
Through the help you can see all the options available to you
1 | $ minicom -h |
Tips
If the terminal output contains this line, you might need to type
sudo minicom
.
1 /dev/ttyUSB0: Permission deniedTo access U-boot, leave your USB-Serial-Debug tool connected, then press the
reset
button on your device once. You should see some print-out on your terminal, then quickly press thespace-bar
orcontrol-c
to stop auto-boot. You will see the prompt kvim# when you’ve entered u-boot.Note that to see the standard “help” commands as listed in the U-Boot Usage Guide, you’ll need to first have a version of Android or Ubuntu installed in your VIM device, from our krescue images.
You can use the U-Boot command line (kvim#), to change your VIM’s default boot logo.bmp, according to the guide, Boot Logo for U-Boot.