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How to put STM32 Blue Pill in runnig mode?

#stm32 #bluepill #stm32f103c8t6 #cp2102

Getting an STM32 Blue Pill(STM32F103C8T6) "running" means configuring it to start executing your program from flash memory. This is usually straightforward, but there are a few key things to check.

The Short Answer: Boot Pin Configuration
The STM32's startup behavior is controlled by the BOOT0 and BOOT1 pins. To run your programmed code, you need the following configuration:

  • BOOT0 = 0 (LOW, connected to GND)
  • BOOT1 = 0 (LOW, connected to GND) - Note: BOOT1 is often labeled as PB2 on the pinout.

This is the "Normal Boot Mode" or "Main Flash Memory" mode. On power-up or reset, the microcontroller will begin executing the program you've uploaded to its internal flash memory starting at address 0x0800 0000.

Here's a visual of the correct configuration:

text |-----------------------| | STM32F103 | | Blue Pill | | | | [ ] [ ] [ ] [ ] | | [ ] [ ] [ ] [ ] | | [ ] [ ] [ ] [ ] | |-----------------------| | | 3.3V GND | | | | | | | | | | | | | | | | | | | | | BOOT0 | | BOOT1 | | Pin | | Pin | |________| |_______| (Also PB2) CONNECT BOTH TO GND (0) FOR NORMAL RUN MODE
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Step-by-Step Guide to "Running Mode"
Step 1: Hardware Configuration (Boot Pins)

  1. Locate the Boot Pins: On the Blue Pill, you'll see two small solder jumpers near the top, labeled BOOT0 and BOOT1 (or sometimes just B0 and B1).

  2. Set BOOT0 to 0:

  • The BOOT0 jumper should have a header connecting it to the 0 position (which is connected to GND).
  • If it's connected to 1 (3.3V), move the jumper to the 0 position.
  1. Set BOOT1 to 0:
  • The BOOT1 jumper should also be connected to the 0 position.
  • On many Blue Pills, BOOT1 is shared with the GPIO pin PB2. For normal operation, it just needs to be low (0).

Correct Configuration for Running:

  • BOOT0 Jumper: 0 (GND)
  • BOOT1 Jumper: 0 (GND)

Step 2: Power and Reset

  1. Provide power to the Blue Pill via the 5V or 3.3V pins, or through the USB port (if your board has a USB-serial chip installed).
  2. Press the RESET button (if your board has one). The MCU will now read the boot pins and begin executing your program from flash memory.

Troubleshooting: If Your Program Doesn't Run
If you've uploaded a program but nothing happens, follow this checklist:

1. Double-Check the Boot Pins (Most Common Issue!)
This is the #1 reason a Blue Pill won't run a programmed application.

  • Symptom: The board powers on but does nothing, or it only runs the program after pressing reset.
  • Solution: Ensure BOOT0 is definitely connected to GND (0). Use a multimeter to check for continuity if you're unsure.

2. Verify the Program was Uploaded Correctly

  • Symptom: A blank board (a new Blue Pill) or a board that was previously working but now isn't.

  • Solution:

    • Use an ST-Link programmer or a USB-TTL adapter to upload a simple "Blink" test program.
    • Confirm the upload process finished without errors in your IDE (STM32CubeIDE, Arduino IDE, etc.).

3. Check the Power Supply

  • Symptom: The board behaves erratically or fails to start.
  • Solution: Ensure you have a stable 3.3V power supply. The onboard 3.3V regulator is not very robust. Try powering via the 3.3V pin from a stable external source.

4. Inspect the Oscillators

  • Symptom: The program uploads but doesn't run, or timing is completely wrong.

  • Solution:

    • The Blue Pill requires an external 8MHz crystal for the main clock. Cheaper boards sometimes have faulty or missing crystals.
    • Check that the two small metal crystals (usually 8MHz and 32.768kHz) are properly soldered.

How to Re-Program the Blue Pill (Uploading a New Program)
To upload a new program, you often need to put the board into a state where the bootloader is active.

Method 1: Using the Bootloader (via UART)
This is the classic method, requiring a USB-to-TTL Serial adapter (like CP2102 or FTDI).

  1. Set Boot Pins for Bootloader Mode:
  • BOOT0 = 1 (connect to 3.3V)
  • BOOT1 = 0 (connect to GND)

  1. Press the RESET button. The board will now run the built-in ROM bootloader and wait for a connection on UART1 (PA9 & PA10).

  2. Connect your USB-to-TTL adapter:

  • Adapter TX -> MCU RX (PA10)
  • Adapter RX -> MCU TX (PA9)
  • Adapter GND -> MCU GND
  • Adapter 3.3V can be used to power the board.

  1. Use a tool like STM32CubeProgrammer or the Arduino IDE to upload the new program via the serial port.

  2. CRUCIAL STEP: After uploading, set the BOOT0 jumper back to 0 (GND) and press RESET. The board will now boot into your new program.

Method 2: Using an ST-Link Debugger (Recommended)
This is the most reliable and professional method.

  1. You do NOT need to change the boot pins. The ST-Link forces the MCU into programming mode via the SWD interface.

  2. Connect the ST-Link to the Blue Pill's SWD header:

  • ST-Link VCC -> 3.3V (Optional, but provides power)
  • ST-Link GND -> GND
  • ST-Link SWDIO -> DIO (PA13)
  • ST-Link SWCLK -> CLK (PA14)

  1. In your IDE (STM32CubeIDE, Keil, etc.), select "Download" or "Load". The program will be uploaded and verified.

  2. Press the RESET button on the Blue Pill. With BOOT0=0, it will immediately run your new program.

Summary

To put your STM32 Blue Pill in running mode: Ensure BOOT0 is connected to GND (0), and press RESET. If it still doesn't work, the program itself or the clock configuration might be the issue.

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