목차
[WAT-STM32-2.8] 12번 예제 RCC 헤더파일
WAT-STM32-2.8 예제 중 12번째로 RCC 헤더 파일을 사용하는 예제입니다.
주요 코드
RCC.h, RCC.c 헤더파일을 생성하여 RCC 기능을 분리하였습니다.
#ifndef __RCC_H
#define __RCC_H
#define RCC_APB2Periph_AFIO ((uint32_t)0x00000001)
#define RCC_APB2Periph_GPIOA ((uint32_t)0x00000004)
#define RCC_APB2Periph_GPIOB ((uint32_t)0x00000008)
#define RCC_APB2Periph_GPIOC ((uint32_t)0x00000010)
#define RCC_APB2Periph_GPIOD ((uint32_t)0x00000020)
typedef struct
{
__IO uint32_t CR;
__IO uint32_t CFGR;
__IO uint32_t CIR;
__IO uint32_t APB2RSTR;
__IO uint32_t APB1RSTR;
__IO uint32_t AHBENR;
__IO uint32_t APB2ENR;
__IO uint32_t APB1ENR;
__IO uint32_t BDCR;
__IO uint32_t CSR;
} RCC_TypeDef;
/************ RCC Adress 지정 *************/
#define AHBPERIPH_BASE (PERIPH_BASE + 0x20000)
#define RCC_BASE (AHBPERIPH_BASE + 0x1000)
#define RCC ((RCC_TypeDef *) RCC_BASE)
void RCC_init(void);
#endif
#include "main.h"
#include "rcc.h"
void RCC_init() // RCC_init() 함수
{
// Clock control register
// Bit17 HSERDY: External high-speed clock ready flag
// Bit16 HSEON: External high-speed clock enable
unsigned char sws = 0;
RCC->CR |= 0X00010000; // HSEON
while(!(RCC->CR>>17)); //HSE 준비될때까지 기다림
// Clock configuration register (RCC_CFGR)
// Bits21:18 PLLMUL: PLL multiplication factor
// Bits10:8 PPRE1: APB low-speed prescaler (APB1)
/* Bit10-8 0x100 100: HCLK divided by 2 */
RCC->CFGR = 0x00000400;
/*
0000：PLL input clock x 2 1000：PLL input clock x 10
0001：PLL input clock x 3 1001：PLL input clock x 11
0010：PLL input clock x 4 1010：PLL input clock x 12
0011：PLL input clock x 5 1011：PLL input clock x 13
0100：PLL input clock x 6 1100：PLL input clock x 14
0101：PLL input clock x 7 1101：PLL input clock x 15
0110：PLL input clock x 8 1110：PLL input clock x 16
0111：PLL input clock x 9 1111：PLL input clock x 16
*/
RCC->CFGR |= 7<<18; // PLL input clock x 9 -> 72MHz
RCC->CFGR |= 1<<16; //1: HSE oscillator clock selected as PLL input clock
FLASH->ACR|=0x32;
RCC->CR |= 1<<24; //1: PLL ON
while(!(RCC->CR>>25)); //0: PLL unlocked 기다림
RCC->CFGR |= 1<<1; //10: PLL selected as system clock
while(sws != 0x2) // 10: PLL used as system clock
{
sws = RCC->CFGR>>2; // Bits3:2 10: PLL used as system clock
sws &= 0x3;
}
}
RCC 를 헤더파일로 구성하여 main.c 코드는 더 간소화 되었습니다.
// WAT_STM3228_12 RCC 헤더 파일 추가
// 1초 간격으로 LED2 ON/OFF
//
// 출처: https://docs.whiteat.com/?p=3676
//
#include "main.h"
#include "rcc.h"
#define LEDON (GPIOB->BRR = GPIO_Pin_2)
#define LEDOFF (GPIOB->BSRR = GPIO_Pin_2)
void LED_init()
{
/* GPIOB Port Enable*/
RCC->APB2ENR |= RCC_APB2Periph_GPIOB;
/*-- GPIO Mode Configuration speed, input/output -----------------------*/
/*-- GPIOB max speed: 50MHz , General purpose output push-pull ---*/
GPIOB->CRL &= 0xFFFFF0FF;
GPIOB->CRL |= 0x00000300;
}
void Delay(vu32 nCount) //delay
{
for(; nCount != 0; nCount--);
}
int main(void)
{
RCC_init(); //RCC 초기화
LED_init(); //LED 초기화
while (1)
{
LEDON; // LED ON
Delay(0x17FFFF*5); // delay
LEDOFF; // LED OFF
Delay(0x17FFFF*5); // delay
}
}
결과화면
앞의 예제와 동일하게 1초마다 ON/OFF 합니다.
WAT-STM32-2.8보드 전체 예제
제품 구매
WAT-STM32-2.8 [STM32F103RB Board + 2.8인치 TFT LCD 터치 세트] 는 https://kit128.com/goods/view?no=221 에서 구매하실 수 있습니다.
