STM32 Firmware

Firmware update

Note

The contents of this chapter are hosted in the unit_ch55x_docker_sdk.git repository. Always remember to keep Docker Desktop open in your computer; otherwise, the commands will not work properly.

To start using your CH552 USB Multi-Protocol Programmer as a PICO DAP, follow these steps:

cd unit_ch55x_docker_sdk

Once you are at the main directory, open a terminal and enter the commands:

Linux

./spkg/spkg -p ./examples/USB/Prog/PICO-DAP

Windows

./spkg/spkg.bat -p ./examples/USB/Prog/PICO-DAP

The command creates a .bin file inside the build folder.

WCHIspStudio

Then open WCHIspStudio to upload the firmware

Settings WCHIspStudio

• In Object File 1 make sure to enter the correct path to the directory with the firmware.

• Make sure the “Automatic Download When Device Connect” option is enabled.

• To add the path you have to click on this bottom “…” and check.

Warning

Before connecting your Multi-Protocol Programmer, make sure to power it with +5V. You can do this by setting your switch to +5V.

• Push the Boot bottom and connect your Multi-Protocol Programmer to your computer.

• Wait until de firmware has finished updating your device.

Done! Now you can use your UNIT CH552 Multi-Protocol Programmer!

Create a new project in PlatformIO

Installation

Open Visual Studio Code, in the extensions menu, search PlatformIO:

PlatformIO extension in Visual Studio Code

And install the official version from PlatformIO:

PlatformIO extension

In the Activity Bar, you will find the icon of your new extension in Visual Studio Code.

In the general menu, click on “Create New Project”

General menu

In the Quick Access menu, we can open an existing file for our STM32F4xx or create a new one:

Quick Access menu

Next, in the Project Wizard:

• We will name our file.

• Select the specific model of our STM32F4xx board.

• Choose the framework (for this example, we will use CMSIS)

• Specify the location where we want to save the project.

Project Wizard

Project

Inside the generated project, you will find this project structure.

Project structure

If you need to change your COM port, follow these steps:

New COM port

Inside the .ini file, make sure you have this configuration:

[env:blackpill_f411ce]
platform = ststm32
board = blackpill_f411ce
framework = cmsis
upload_protocol = cmsis-dap
debug_tool = cmsis-dap

Note

If you are using a different board, change the “[env: …]” and “board = …” to match your board model.

Here is a list of common STM32 microcontrollers and their corresponding board identifiers used in PlatformIO’s platformio.ini file.

Table 9 STM32 Microcontrollers

Microcontroller / Board	PlatformIO board name
STM32F103C8 (Blue Pill)	bluepill_f103c8
STM32F401RE (Nucleo)	nucleo_f401re
STM32F446RE (Nucleo)	nucleo_f446re
STM32F103RB	genericSTM32F103RB
STM32F407VG (Discovery)	disco_f407vg
STM32F411CEU6 (Blackpill)	blackpill_f411ce

Example

The following example is a Blink using GPIOC (PC13) as an output.

#include "stm32f4xx.h"

// Simple software delay loop
void delay(volatile uint32_t t) {
    while (t--);
}

int main(void) {
    // 1. Enable the clock for GPIOC (required before accessing GPIOC registers)
    RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN;

    // 2. Configure pin PC13 as general-purpose output (MODER13 = 0b01)
    GPIOC->MODER &= ~(0x3 << (13 * 2)); // Clear MODER13 bits
    GPIOC->MODER |=  (0x1 << (13 * 2)); // Set MODER13 to output mode

    // 3. Main loop
    while (1) {
        GPIOC->ODR ^= (1 << 13); // Toggle PC13 (invert LED state)
        delay(500000);           // Simple delay (not accurate, for testing purposes)
    }
}

Flashing

• Once you have your example ready to upload, just click on the PlatformIO icon on the Activity Bar.

• Select the “Upload” option.

Flashing

Note

To program a STM32F4xx, use the SWD protocol. For more information, check the pinout.

Warning

The STM32F4xx operates at 3.3V. Switch to 3.3V before connecting your device.