STM32

Project STM32
STM32 setup guide
Status	In progress
Contact	bertrik
Last Update	2018-05-16

Introduction

This page is about inexpensive microcontroller boards containing an STM32 processor and how to get them to work.

You can find these boards on AliExpress for less than €2,- if you search for "stm32f103c8t6". Yet they have nice specifications, see also http://www.st.com/en/microcontrollers/stm32f103c8.html

To name a few:

• 32-bit ARM Cortex-M3 processor running at up to 72 MHz
• 128 kB flash memory, 20 kB SRAM
• USB and CAN controllers
• 32 kHz crystal for RTC
• dual 1 us A/D converter, DMA controller
• the usual stuff like SPI, UART, I2C

They are even Arduino compatible, see:

• Arduino for STM32
• Arduino goes STM32, a quick tutorial
• Arduino STM32 page of Roger Clark

Another, very similar, guide to getting started with STM32 and Arduino.

Setting up the tool chain

This describes the steps I did to get a "blue pill" board to work on Debian Jessie.

Arduino IDE

Steps to set up the IDE:

• get and install the latest Arduino IDE from here.
• under menu Tools / Board / Board Manager, search for "zero" and install the Arduino Zero toolchain
• get the Arduino_STM32 source code, for example, run in the console:

cd ~/code
mkdir stm32
cd stm32
git clone https://github.com/rogerclarkmelbourne/Arduino_STM32

• create a symlink to the Arduino_STM32 source tree in your ~/Arduino/hardware directory, for example:

cd ~/Arduino/hardware
ln -s ~/code/stm32/Arduino_STM32 .

• restart the Arduino IDE.

Platform IO configuration

Below is an example platformio configuration for a blue pill with the USB bootloader. Save this to a file named platformio.ini in the directory where the .ino file is, and run it with 'pio run'.

[platformio]
src_dir = .

[env:bluepill_f103c8]
platform = ststm32
board = bluepill_f103c8
framework = arduino
upload_protocol = dfu

stm32flash

If you're running a 64-bit Linux, it can be convenient to add support for the 32-bit stm32flash utility, run:

sudo apt-get install libc6-i386

The tool chain installation should now be ready.

Hardware

The hardware I'm using, is the blue pill, I soldered on the headers for easy plugging with dupont-wire. You'll also need a USB-serial converter.

I hooked it up as follows:

• converter 5V -> board 5V
• converter GND -> board GND
• converter RXD -> board A9
• converter TXD -> board A10

To put the board into programming mode, set the BOOT0 jumper to the "1" position and the BOOT1 jumper to the "0" position, then push the reset button.

To just run the program that was last flashed into the board, set both the BOOT0 and the BOOT1 jumper to the "0" position.

Software

To load your application using the Arduino IDE:

• in the Arduino IDE, under menu Tools / Board, select "Generic STM32F103C Series"
• in the Arduino IDE, under menu Tools / Upload Method, select "Serial"
• use the following program to blink the on-board LED:

#define pinLED PC13

void setup() {
  pinMode(pinLED, OUTPUT);
}

void loop() {
  digitalWrite(pinLED, HIGH);
  delay(200);
  digitalWrite(pinLED, LOW);
  delay(100);
}

• make sure you have the BOOT jumpers in the right position and press the reset button (BOOT0->1, BOOT1->0)
• ctrl-U to upload it to the board, the program will start automatically
• to make the program run after each reboot, place the BOOT0 jumper back to its original position.

The Arduino console should show something like this:

Sketch uses 7,140 bytes (5%) of program storage space. Maximum is 131,072 bytes.
Global variables use 1,984 bytes of dynamic memory.
/home/bertrik/Arduino/hardware/Arduino_STM32/tools/linux/serial_upload ttyUSB0 {upload.altID} {upload.usbID} /tmp/arduino_build_33274/stm32.ino.bin 
stm32flash Arduino_STM32_0.9

http://github.com/rogerclarkmelbourne/arduino_stm32

Using Parser : Raw BINARY
Interface serial_posix: 230400 8E1
Version      : 0x22
Option 1     : 0x00
Option 2     : 0x00
Device ID    : 0x0410 (Medium-density)
- RAM        : 20KiB  (512b reserved by bootloader)
- Flash      : 128KiB (sector size: 4x1024)
- Option RAM : 16b
- System RAM : 2KiB
Write to memory
Erasing memory

Wrote address 0x08000100 (3.59%) 
Wrote address 0x08000200 (7.17%) 
...
Wrote address 0x08001be4 (100.00%) Done.

Starting execution at address 0x08000000... done.

Unlocking/erasing the first time

You might find that the flash is protected on a new board, this means you cannot put your own program on the board. You can fix this as follows:

• go the stm32flash directory

cd ~/Arduino/hardware/Arduino_STM32/tools/linux/stm32flash

• use the stm32flash utility to disable the flash-read protection

./stm32flash /dev/ttyUSB0 -k

Flashing the USB bootloader

The USB bootloader makes it easy/fast to upload new software into the board without having the move the jumpers.

For the blue pill the steps to install the bootloader are as follows:

• cd into the directory Arduino_STM32/tools/linux/stm32flash
• ./stm32flash -w ~/code/stm32/STM32duino-bootloader/binaries/generic_boot20_pc13.bin -v -g 0x0 /dev/ttyUSB0

Future work

Investigate the Blackmagic debugging firmware. This should allow you to debug your applications (e.g. step through code in an IDE such as eclipse). See also:

• https://nuft.github.io/arm/2015/08/24/blackmagic-stlink.html
• https://medium.com/@paramaggarwal/converting-an-stm32f103-board-to-a-black-magic-probe-c013cf2cc38c#.h2md3y5hl