GPIO Digital
CMSIS
Tutorial Code: LED Toggle
/**
******************************************************************************
* @author SSSLAB
* @Mod 2021-8-12 by YKKIM
* @brief Embedded Controller: Tutorial Digital In
* - Turn on LED LD2 while Button B1 is pressing
*
******************************************************************************
*/
// GPIO Mode : Input(00), Output(01), AlterFunc(10), Analog(11, reset)
// GPIO Speed : Low speed (00), Medium speed (01), Fast speed (10), High speed (11)
// GPIO Output Type: Output push-pull (0, reset), Output open drain (1)
// GPIO Push-Pull : No pull-up, pull-down (00), Pull-up (01), Pull-down (10), Reserved (11)
#include "stm32f4xx.h"
#define LED_PIN 5 //LD2
#define BUTTON_PIN 13
void RCC_HSI_init(void); //defined in ecRcc.h
void RCC_GPIOA_enable(void);
void RCC_GPIOC_enable(void);
int main(void) {
/* Part 1. RCC GPIOA Register Setting */
RCC_GPIOA_enable();
RCC_GPIOC_enable();
/* Part 2. GPIO Register Setting for OUTPUT*/
// GPIO Mode Register
GPIOA->MODER &= ~(3UL<<(2*LED_PIN)); // Clear '00' for Pin 5
GPIOA->MODER |= 1UL<<(2*LED_PIN); // Set '01' for Pin 5
// GPIO Output Type Register
GPIOA->OTYPER &= ~(1UL<<LED_PIN); // 0:Push-Pull
// GPIO Pull-Up/Pull-Down Register
GPIOA->PUPDR &= ~(3UL<<(2*LED_PIN)); // 00: none
// GPIO Output Speed Register
GPIOA->OSPEEDR &= ~(3UL<<(2*LED_PIN));
GPIOA->OSPEEDR |= 2UL<<(2*LED_PIN); //10:Fast Speed
/* Part 3. GPIO Register Setting for INPUT*/
// GPIO Mode Register
GPIOC->MODER &= ~(3UL<<(2*BUTTON_PIN)); // 00: Input
// GPIO Pull-Up/Pull-Down Register
GPIOC->PUPDR &= ~(3UL<<(2*BUTTON_PIN));
GPIOC->PUPDR |= 2UL<<(2*BUTTON_PIN); // 10: Pull-down
/* Part 4. Deal loop */
while(1){
unsigned int btVal=0;
//Read bit value of Button
btVal=(GPIOC->IDR) & (1UL << BUTTON_PIN);
if(btVal == 0)
GPIOA->ODR |= (1UL << LED_PIN);
else
GPIOA->ODR &= ~(1UL << LED_PIN);
}
}
void RCC_GPIOA_enable()
{
// HSI is used as system clock
RCC_HSI_init();
// RCC Peripheral Clock for GPIO_A Enable
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN;
}
void RCC_GPIOC_enable()
{
// HSI is used as system clock
RCC_HSI_init();
// RCC Peripheral Clock for GPIO_A Enable
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN;
}
void RCC_HSI_init() {
// Enable High Speed Internal Clock (HSI = 16 MHz)
RCC->CR |= ((uint32_t)RCC_CR_HSION);
// wait until HSI is ready
while ( (RCC->CR & (uint32_t) RCC_CR_HSIRDY) == 0 ) {;}
// Select HSI as system clock source
RCC->CFGR &= (uint32_t)(~RCC_CFGR_SW);
RCC->CFGR |= (uint32_t)RCC_CFGR_SW_HSI;
// Wait till HSI is used as system clock source
while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != 0 );
}
void bit_toggle(unsigned int pinNum){
GPIOA->ODR ^= 1<<pinNum;
}
}
}
HAL
ecGPIO.h (partial code)
#include "stm32f411xe.h"
#ifndef __EC_GPIO_H
#define __EC_GPIO_H
#define INPUT 0x00
#define OUTPUT 0x01
#define AF 0x02
#define ANALOG 0x03
#define HIGH 1
#define LOW 0
#define LED_PIN 5
#define BUTTON_PIN 13
void GPIO_init(GPIO_TypeDef *Port, int pin, int mode);
void GPIO_write(GPIO_TypeDef *Port, int pin, int Output);
int GPIO_read(GPIO_TypeDef *Port, int pin);
void GPIO_mode(GPIO_TypeDef* Port, int pin, int mode);
void GPIO_ospeed(GPIO_TypeDef* Port, int pin, int speed);
void GPIO_otype(GPIO_TypeDef* Port, int pin, int type);
void GPIO_pudr(GPIO_TypeDef* Port, int pin, int pudr);
#endifecGPIO.cpp (a partial code)
#include "stm32f4xx.h"
#include "stm32f411xe.h"
#include "ecGPIO.h"
void GPIO_init(GPIO_TypeDef *Port, int pin, int mode){
if (Port == GPIOA)
RCC_GPIOA_enable();
if (Port == GPIOC)
RCC_GPIOC_enable();
// Make it for GPIOB, GPIOD..GPIOH
// You can make a more general function of
// void RCC_GPIO_enable(GPIO_TypeDef *Port);
GPIO_mode(Port, pin, mode);
// The rest are default values
}
//int main(void)
//{
//
// GPIO_mode(GPIOA, LED_PIN,0);
//
//}
// GPIO Mode : Input(00), Output(01), AlterFunc(10), Analog(11, reset)
void GPIO_mode(GPIO_TypeDef *Port, int pin, int mode){
Port->MODER &= ~(3UL<<(2*pin));
Port->MODER |= mode<<(2*pin);
}
Example code for LAB: LED toggle
Tutorial_DigitalInOut_LED_Button_HAL.c
/**
******************************************************************************
* @author SSSLAB
* @Mod 2021-8-12 by YKKIM
* @brief Embedded Controller: LAB Digital In/Out
* - Toggle LED LD2 by Button B1 pressing
*
******************************************************************************
*/
#include "stm32f4xx.h"
#include "myGPIO.h"
#include "myRCC.h"
#define LED_PIN 5
#define BUTTON_PIN 13
void setup(void);
int main(void) {
// Initialiization --------------------------------------------------------
setup();
// Inifinite Loop ----------------------------------------------------------
while(1){
if(GPIO_read(GPIOC, BUTTON_PIN) == 0) GPIO_write(GPIOA, LED_PIN, HIGH);
else GPIO_write(GPIOA, LED_PIN, LOW);
}
}
// Initialiization
void setup(void)
{
RCC_HSI_init();
GPIO_init(GPIOC, BUTTON_PIN, INPUT); // calls RCC_GPIOC_enable()
GPIO_init(GPIOA, LED_PIN, OUTPUT); // calls RCC_GPIOA_enable()
}Application API
EC_GPIO.h
#include "stm32f411xe.h"
#include "ecGPIO.h"
#include "ecRCC.h"
#ifndef __EC_GPIO_API_H
#define __EC_GPIO_API_H
#define EC_DOUT 1
#define EC_DIN 0
#define EC_PU 1
#define EC_PD 0
#define EC_NONE 0
#define EC_LOW 0
#define EC_MEDIUM 1
#define EC_FAST 2
#define EC_HIGH 3
#define LED_PIN 5
#define BUTTON_PIN 13
/* System CLOCK is HSI by default */
class EC_DigitalIn
{
public:
EC_DigitalIn(GPIO_TypeDef *Port, int pin)
{
uint8_t mode=EC_DIN; // mode=0
GPIO_init(Port, pin, mode);
Port_t=Port;
pin_t=pin;
mode_t=mode;
}
~EC_DigitalIn()
{
delete[] Port_t;
}
int read()
{
val_t=GPIO_read(Port_t, pin_t);
return val_t;
}
void pupdr(int _pupd){
GPIO_pudr(Port_t, pin_t, _pupd);
}
operator int()
{
return read();
}
private:
GPIO_TypeDef *Port_t;
int pin_t;
int mode_t;
int val_t;
};
class EC_DigitalOut
{
public:
EC_DigitalOut(GPIO_TypeDef *Port, int pin);
// Exercise. Define the function in EC_GPIO.cpp
~EC_DigitalOut()
{
delete[] Port_t;
}
void write(int _outVal);
// Exercise. Define the function in EC_GPIO.cpp
void pupdr(int _pupd);
// Exercise. Define the function in EC_GPIO.cpp
void otype(int _type);
// Exercise. Define the function in EC_GPIO.cpp
void ospeed(int _speed);
// Exercise. Define the function in EC_GPIO.cpp
EC_DigitalOut &operator= (int value)
{
write(value);
return *this;
}
int read()
{
return GPIO_read(Port_t, pin_t);
}
operator int()
{
// Underlying call is thread safe
return read();
}
private:
GPIO_TypeDef *Port_t;
int pin_t;
int mode_t;
};
#endifEC_GPIO.cpp
#include "EC_GPIO.h"
/* System CLOCK is HSI by default */
EC_DigitalOut::EC_DigitalOut(GPIO_TypeDef *Port, int pin)
{
uint8_t mode=EC_DOUT; // mode=1;
GPIO_init(Port, pin, mode);
this->Port_t=Port;
this->pin_t=pin;
this->mode_t=mode;
}
void EC_DigitalOut::write(int _outVal)
{
GPIO_write(Port_t, pin_t, _outVal);
}
void EC_DigitalOut::pupdr(int _pupd){
GPIO_pudr(Port_t, pin_t, _pupd);
}
void EC_DigitalOut::otype(int _type){
GPIO_otype(Port_t, pin_t, _type);
}
void EC_DigitalOut::ospeed(int _speed){
GPIO_ospeed(Port_t, pin_t, _speed);
}
Example code for LAB: LED toggle
Tutorial_DigitalInOut_LED_Button_API.
/**
******************************************************************************
* @author SSSLAB
* @Mod 2021-8-12 by YKKIM
* @brief Embedded Controller: LAB Digital In/Out with API
* - Toggle LED LD2 by Button B1 pressing
*
******************************************************************************
*/
#include "EC_GPIO.h"
#define LED_PIN 5
#define BUTTON_PIN 13
EC_DigitalIn button(GPIOC,BUTTON_PIN);
EC_DigitalOut led(GPIOA,LED_PIN);
int main(void) {
// Initialiization --------------------------------------------------------
// Inifinite Loop ----------------------------------------------------------
while(1){
//if(button.read() == 0) led.write(HIGH);
//else led.write(LOW);
if(!button) led=1;
else led=0;
}
}mbed
#include "mbed.h"
DigitalIn button(USER_BUTTON);
DigitalOut led(LED1);
int main() {
while(1) {
if(!button) led = 1;
else led = 0;
}
}Last updated