STM32 Programming from Scratch
Welcome to Think Electronic Circuits!
In this tutorial you can learn how to make a project for STM32 microcontroller using CMSIS and after that how to write a code for LED blink.
Requirement for this project:-
Software:-
Select C file and give name of file as main and select "ADD" option.
The coding part:-
1)Include the header file of microcontroller in main.c
In main write the relevant code:-
start with declaring the declaring the structure pointer to RCC_TypeDef and pointer to GPIO_TypeDef
RCC_TypeDef *clock;
GPIO_TypeDef *GPIO;
Assign the address of GPIOA and RCC to respective pointers.
clock=RCC;
GPIO=GPIOA;
Select the clock source of microcontroller unit.I am using HSE in this code
clock->CR &=0x00000000;
clock->CR |=(1<<16);//clock source is on board 8 MHz crytal
Initialise the other required register also.
while(!((clock->CR)&(1<<17)));//Wait till HSERDY FLAG IS SET
clock->CFGR &=0x00000000;
clock->CFGR|=0xA0;//1MHz clock set in RCC,clock divider is 8
clock->AHB2ENR&=0x00000000;
clock->AHB2ENR|=0x01;//clock of port A is set
Initialize the GPIO registers also.
GPIO->MODER &=(1<<10);
GPIO->OTYPER &=0x00;
GPIO->OSPEEDR|=0x1100;
GPIO->PUPDR|=0x00000000;
GPIO->ODR &=0x00000000;
add code in infinite while loop also
while(1){
GPIO->ODR^=(1<<5);
for(long unsigned int i=0;i<1000000;i++)__nop();/*1SEC DELAY 1 MHZ CLOCK TO THE PORT A 1/1000000=10^-6;10^-6 *10^6=1sec*/
}
The complete source code:-
#include "stm32l4xx.h"
int main(){
RCC_TypeDef *clock;//pointer to RXX
GPIO_TypeDef *GPIO;
clock=RCC;
GPIO=GPIOA;
clock->CR &=0x00000000;
clock->CR |=(1<<16);//clock source is on board 8 MHz crytal //
while(!((clock->CR)&(1<<17)));//Wait till HSERDY FLAG IS SET
clock->CFGR &=0x00000000;
clock->CFGR|=0x0A;//1MHz clock set in RCC,clock divider is 8
clock->AHB2ENR&=0x00000000;
clock->AHB2ENR|=0x01;//clock of port A is set
GPIO->MODER &=(1<<10);
GPIO->OTYPER &=0x00;
GPIO->OSPEEDR|=0x1100;
GPIO->PUPDR|=0x00000000;
GPIO->ODR &=0x00000000;
while(1){
GPIO->ODR^=(1<<5);
for(long unsigned int i=0;i<1000000;i++)__nop();//1SEC DELAY /*1 MHZ CLOCK TO //THE PORT A 1/1000000=10^-6;10^-6 *10^6=1sec*/
}
//return 0;
}
This code will toggle the on board LED of STM32 Nucleo with 1 second delay.
Note:This code will work for all STM32 microcontrollers with change in registers value.Refer your microcontroller's reference manual and datasheet.This code have been tested for STM32L476RG nucleo board.
In this tutorial you can learn how to make a project for STM32 microcontroller using CMSIS and after that how to write a code for LED blink.
Requirement for this project:-
Software:-
- Keil uvision5
- STM32L476 Nucleo board(any other nucleo baord from ST will also work)
- USB
Steps to make a new project in keil:-
- Open Keil in your PC:
- Go to Project->New uvision Project
- Give a Project Name and save it.
- Select the Microcontroller you are using (on your board)and select ok.
- Manage Run time environment will be opened.Select two option a shown in below figure.(shown by tick mark).Core (under CMSIS) and Startup(under Device) and select OK.
- Right click on Source group1 and select "Add new item to Source group1"
The coding part:-
1)Include the header file of microcontroller in main.c
In main write the relevant code:-
start with declaring the declaring the structure pointer to RCC_TypeDef and pointer to GPIO_TypeDef
RCC_TypeDef *clock;
GPIO_TypeDef *GPIO;
Assign the address of GPIOA and RCC to respective pointers.
clock=RCC;
GPIO=GPIOA;
Select the clock source of microcontroller unit.I am using HSE in this code
clock->CR &=0x00000000;
clock->CR |=(1<<16);//clock source is on board 8 MHz crytal
Initialise the other required register also.
while(!((clock->CR)&(1<<17)));//Wait till HSERDY FLAG IS SET
clock->CFGR &=0x00000000;
clock->CFGR|=0xA0;//1MHz clock set in RCC,clock divider is 8
clock->AHB2ENR&=0x00000000;
clock->AHB2ENR|=0x01;//clock of port A is set
Initialize the GPIO registers also.
GPIO->MODER &=(1<<10);
GPIO->OTYPER &=0x00;
GPIO->OSPEEDR|=0x1100;
GPIO->PUPDR|=0x00000000;
GPIO->ODR &=0x00000000;
add code in infinite while loop also
while(1){
GPIO->ODR^=(1<<5);
for(long unsigned int i=0;i<1000000;i++)__nop();/*1SEC DELAY 1 MHZ CLOCK TO THE PORT A 1/1000000=10^-6;10^-6 *10^6=1sec*/
}
The complete source code:-
#include "stm32l4xx.h"
int main(){
RCC_TypeDef *clock;//pointer to RXX
GPIO_TypeDef *GPIO;
clock=RCC;
GPIO=GPIOA;
clock->CR &=0x00000000;
clock->CR |=(1<<16);//clock source is on board 8 MHz crytal //
while(!((clock->CR)&(1<<17)));//Wait till HSERDY FLAG IS SET
clock->CFGR &=0x00000000;
clock->CFGR|=0x0A;//1MHz clock set in RCC,clock divider is 8
clock->AHB2ENR&=0x00000000;
clock->AHB2ENR|=0x01;//clock of port A is set
GPIO->MODER &=(1<<10);
GPIO->OTYPER &=0x00;
GPIO->OSPEEDR|=0x1100;
GPIO->PUPDR|=0x00000000;
GPIO->ODR &=0x00000000;
while(1){
GPIO->ODR^=(1<<5);
for(long unsigned int i=0;i<1000000;i++)__nop();//1SEC DELAY /*1 MHZ CLOCK TO //THE PORT A 1/1000000=10^-6;10^-6 *10^6=1sec*/
}
//return 0;
}
This code will toggle the on board LED of STM32 Nucleo with 1 second delay.
Note:This code will work for all STM32 microcontrollers with change in registers value.Refer your microcontroller's reference manual and datasheet.This code have been tested for STM32L476RG nucleo board.
Amazon link to Stm32 nucleo board:https://amzn.to/3BBuNvi
Amazon link to Hantek oscilloscope:https://amzn.to/3ocbo0S
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