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dma-cpp

README.md

DMA operation with USART1 in C++

Achieve USART communication with DMA in Circular, 1shot and Echo mode. The complete development flow is independent of any IDE or tools. This project code can be editied on any text editor and uploaded to the board using drivers provided by STMicro-electronics.

Dependencies

  • make
    Make utility is required for configuring and building this project. You can install make on linux by running command:

    sudo apt install build-essential

  • gcc-arm-none-eabi toolchain
    ARM cross-platform toolchain is required to build applications for arm mcus. Toolchain can be installed by running following command:

    sudo apt install gcc-arm-none-eabi

  • openocd
    It is an Open On Circuit Debugging tool used to flash and debug arm micro controllers. You can install openocd on linux by running command:

    sudo apt install openocd -y

  • st-link
    This package is provided by STMicro-electronics for flashing the binary on the micro-controller

sudo apt install stlink

  • Cortex Debug extension
    This extension for VSCode is helpful for debugging the application on Blue Pill. The contents of registers as well as memory are visible in the context menu. Launch VS Code Quick Open (Ctrl+P), paste the following command, and press enter.

    ext install marus25.cortex-debug

Project Structure

  • src directory contains all source files for the project
  • include directory contains all header files for the project

Source file description

  • stm31f1.ld - linker script for STM32F103 MCU
  • src\main.cpp - application code
  • src\startup_stm32f103.cpp - startup script in cpp
  • include\gpio.hpp - slibrary for handling gpio functions
  • system_stm32f1xx.c - clock configuration and system initialization functions
  • STM32F103.svd - contains the description of the system contained in Arm Cortex-M processor-based microcontrollers, in particular, the memory mapped registers of peripherals.

Run Locally

Running the project is super easy. Just clone, build, and flash.

Clone the project

  1. Using https

    git clone https://github.com/csrohit/stm32-startup-cpp.git
cd stm32-startup-cpp

  2. Using ssh

    git clone git@github.com:csrohit/stm32-startup-cpp.git
cd stm32-startup-cpp

Configuration

All the configuration required for building this project is given below.

  1. Build output directory In Makefile, output directory can be configured using variable BUILD_DIR.

  2. Binary name In Makefile, the name of binary can be configured using variable TARGET.

  3. MCU In Makefile, the target mcu can be selected by seting the following flags/variables

    • MCU_FAMILY: Specifies the family, it used to define a maco for inclusion of header files
    • LD_SCRIPT: Specifies path to linker script of the target controller
    • INSTR_SET: Specifies the instruction set to use. e.g. thumb, arm, etc
    • FLOAT_ABI: Specifies the floating point implementation
    • CPU: Specifies the processor on the MCU. e.g. cortex-m3, cortex-m4, etc

Build

Run following command in terminal to generate flashable binaries for blue pill board. Build files will be written to Build Output Directory as configured.

make all

Flash

  1. Connect STlink to PC and blue pill board using swd headers.
  2. Put blue pill board in programming mode.
  3. Run following to flash board with binary.
make flash

Output

Onboard led connected to Pin C13 can be observed to be blinking every second.

Debug

  1. Run the following make command to build the program using debugging flags
make debug
  1. Flash the controller using following command
make flash
  1. Click in Run and Debug option in VsCode sidebar. Then launch Cortex Debug target.

Happy debugging....

Dependency option

-M Outputs a rule suitable for makefile, does not compile the file The generated rule does not have a command

-MM Outputs a rule suitable for makefile, does not compile the file. In the dependencies only include user files, do not include system header files

-MT/-MQ (-MM -MT abc.o) => change the target This changes the name of the target -MT => generates the same string as provided -MQ => replaces value of the make variable in the target (expansation)

-MD => D represents that the preprocessor output should be generated as a side effect and the main compilation happens If -o options is specified then it is taken as name for the preprocessor output with .d else name of input file is taken with extensions as .d To override the name of the pre-processor output file -MF option should be used