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STM32duino - Blue Pill F103C8

The STM32duino board is based on the ARM Cortex M3 core like the Arduino Duo. The version I use is the Blus Pill.

On Hackaday is a good article about STM32 clones: STM32-Clones - the good the bad and the ugly.

USB Fix

Unfortunately the board comes with a 10k pullup resistor from D+ to 3.3V (in the schematic it's a 4.7k). That can cause problems on some PCs. Just take the R10 out and replace it with an 1.5k resistor like shown here:
http://wiki.stm32duino.com/index.php?title=Blue_Pill#Hardware_installation
One might let the 10k resister untouched and just put a 1.8k in parallel. Between 3.3V and pin A1 (PA12).

And here are some useful infos about the pullup resistors on USB:
https://www.beyondlogic.org/usbnutshell/usb2.shtml

Schematic

Here one find the schematic.
Pinout:

Specification

 Model: STM32F103C8T6
 Core: ARM 32 Cortex-M3 CPU
 Debug mode: SWD
 72MHz work frequency
 64K flash memory
 20K SRAM
 2.0-3.6V power, I/O
 Reset(POR/PDR)
 8MHz crystal
 LED on pin PC13

Software

Here is an installation guide here:
http://wiki.stm32duino.com/index.php?title=Installation
and here:
https://github.com/rogerclarkmelbourne/Arduino_STM32/wiki/Installation
Uploading a sketch:
http://wiki.stm32duino.com/index.php?title=Uploading_a_sketch
Debugging with GDB by Hackaday:
https://youtu.be/D-MbC9N5U7o

https://www.arduinolibraries.info/architectures/stm32

I2C over VGA

One can use the I2C bus from the VGA connector.

I2C on the VGA Connector

How to acces the I2C Bus:

or use the VGA Breakout Board.

Workaround

A workaround for Arch Linux:

Add the I2C kernel module:

 $ sudo modprobe i2c-dev

Check your I2C devices:

 $ ls /dev/

You should find somthing like: i2c-0 i2c-1 i2c-2 …
Install the I2C tools:

 $ sudo pacman -S i2c-tools

or on Debian:

 $ sudo apt-get install -y i2c-tools

Find your device:

 $ i2cdetect -l

The result could look like:

  i2c-1	unknown   	i915 gmbus vga                  	N/A

Looking for an I2C device 

 $ sudo i2cdetect -y 1

It should tell you the address of your I2C device.
Now you can comunicate to your devices with these commands:

 $ i2cget
 $ i2cset
 $ i2cdump

Links

License

This manuals is made by Wolfgang Spahn 2018-20.
It is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Creative Commons License