STM32 Blue Pill USB to TTL: Upload First Sketch | ShillehTek

Video Tutorial (Optional)

Watch first if you want to see the full STM32 Blue Pill setup in Arduino IDE using a USB to TTL converter.

Project Overview

In this tutorial, you set up the STM32 Blue Pill (STM32F103C8T6) with a DSD TECH SH-U09C5 USB to TTL converter in the Arduino IDE, then upload your first program for a successful serial output and basic verification.

The STM32 Blue Pill is a low-cost 32-bit ARM Cortex-M3 board with strong performance and lots of peripherals (SPI, I2C, USART, ADC). Since it does not include an onboard USB-to-serial chip, a USB to TTL adapter is used to upload code and view serial output over UART.

• Time: 30 to 60 minutes
• Skill level: Beginner
• What you will build: A working Arduino IDE setup that can upload a first sketch to the STM32 Blue Pill over UART

Parts List

From ShillehTek

• ShillehTek parts and tools collection - optional accessories like jumper wires and breadboards for clean wiring
• ShillehTek Amazon Store (US) - source for pre-soldered boards and related parts
• ShillehTek Amazon Store (Canada) - alternate regional source
• ShillehTek Amazon Store (Japan) - alternate regional source

External

• Pre-soldered STM32 Blue Pill boards - lets you start without soldering
• DSD TECH SH-U09C5 USB to TTL converter - USB to UART bridge for uploading and serial monitoring
• STM32 Arduino core Board Manager URL - installs STM32 support in Arduino IDE
• STM32CubeProgrammer - required upload tool for serial method
• STM32 Blue Pill (pre-soldered example listing) - reference source used in the original tutorial

Note: This tutorial uses UART upload (USB to TTL). You must set BOOT0 to 1 for UART bootloader mode during upload, and your USB to TTL adapter should be set for 3.3V logic.

Step-by-Step Guide

Step 1 - Wire the Blue Pill to the USB to TTL converter

Goal: Create a working UART connection between your computer and the STM32 Blue Pill for uploading code and serial output.

What to do: Connect the STM32 Blue Pill to the DSD TECH SH-U09C5 USB to TTL converter using UART pins.

• RXD (SH-U09C5) to PA9 (RX on Blue Pill)
• TXD (SH-U09C5) to PA10 (TX on Blue Pill)
• GND (SH-U09C5) to GND (Blue Pill)
• VCC (SH-U09C5) to 3.3V (Blue Pill)

What to do: Set the Blue Pill BOOT0 jumper to 1 (UART bootloader mode). Then plug the TTL converter into your computer USB port for power and connectivity.

Expected result: The Blue Pill is powered and ready for UART flashing via the USB to TTL converter.

Step 2 - Install STM32 board support in Arduino IDE

Goal: Add STM32 board definitions so Arduino IDE can compile for the Blue Pill.

What to do: In Arduino IDE, open File > Preferences, then add this URL to Additional Boards Manager URLs:

https://github.com/stm32duino/BoardManagerFiles/raw/main/package_stmicroelectronics_index.json

Click OK. Then go to Tools > Board > Boards Manager, search for STM32, and install STM32 MCU based boards.

Expected result: STM32 boards appear in the Arduino IDE board selection menus.

Step 3 - Select the correct Blue Pill settings in Arduino IDE

Goal: Configure Arduino IDE to target the right STM32F1 board variant and use serial upload.

What to do: In Arduino IDE:

• Go to Tools > Board > STM32 Boards and select Generic STM32F1 series.
• Under Tools > Board Part Number, select BluePill F103C8 (or BluePill F103CB if you have the 128KB flash version).
• Set Upload Method to STM32CubeProgrammer (Serial).
• Set Port to the port associated with your USB to TTL adapter.

Expected result: The IDE is ready to upload to the Blue Pill over UART.

Step 4 - Install STM32CubeProgrammer and set STM32_PRG_PATH

Goal: Install the upload tool required by the Arduino upload method and ensure Arduino can find it.

What to do: Download and install STM32CubeProgrammer from STMicroelectronics (you may need to create a free account): https://www.st.com/en/development-tools/stm32cubeprog.html.

Then set the STM32_PRG_PATH environment variable to the STM32CubeProgrammer bin folder.

macOS: Add this line to ~/.zshrc or ~/.bash_profile:

export STM32_PRG_PATH=/Applications/STMicroelectronics/STM32Cube/STM32CubeProgrammer/STM32CubeProgrammer.app/Contents/MacOs/bin

Apply it:

source ~/.zshrc

or:

source ~/.bash_profile

Windows: Create a new system environment variable:

• Variable Name: STM32_PRG_PATH
• Variable Value: the path to the STM32CubeProgrammer bin directory, for example:

C:\Program Files\STMicroelectronics\STM32Cube\STM32CubeProgrammer\bin

Expected result: Arduino IDE can invoke STM32CubeProgrammer for serial uploads.

Step 5 - Upload your first program

Goal: Upload a simple sketch and confirm communication using Serial Monitor.

What to do: Create a new Arduino sketch and use this example:

Code:

void setup() {
  // Start the Serial communication at 9600 baud
  Serial.begin(9600);

  // Wait for the serial port to connect (necessary for some boards)
  while (!Serial) {
    ; // Wait
  }
}

void loop() {
  // Print a message to the Serial Monitor
  Serial.println("Hello, Blue Pill!");

  // Wait for 1 second
  delay(1000);
}

Before clicking Upload, press the Reset button on the Blue Pill to ensure it is ready to receive the program. Then click Upload in Arduino IDE.

Note: If the upload does not start, double-check the selected port, your wiring, BOOT0 position, and that STM32_PRG_PATH is set correctly.

Expected result: The upload completes, you see the onboard LED blink at intervals, and the Serial Monitor prints the message once per second.

Conclusion

You just set up the STM32 Blue Pill (STM32F103) in the Arduino IDE using a USB to TTL converter, installed STM32 support, configured serial upload with STM32CubeProgrammer, and uploaded your first working sketch.

Want the exact parts used in this build? Grab them from ShillehTek.com. If you want help customizing this setup for a product, fixture, or production workflow, check out our consulting: https://shillehtek.com/pages/iot-consulting.

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