stm32f103c8t6 VGA简单显示程序,加注释
时间: 2023-09-30 22:04:46 浏览: 172
以下是一份简单的STM32F103C8T6 VGA显示程序,附有注释:
```c
#include "stm32f10x.h"
#define HSYNC_Pin GPIO_Pin_2
#define VSYNC_Pin GPIO_Pin_3
/* VGA分辨率为640x480,像素时钟频率为25.175 MHz */
#define H_PIXEL_FREQ 640
#define V_LINE_FREQ 480
#define PIXEL_CLK_FREQ 25175000
void GPIO_Configuration(void);
void VGA_TIM_Configuration(void);
int main(void)
{
GPIO_Configuration(); // 配置GPIO
VGA_TIM_Configuration(); // 配置定时器
while(1);
}
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* 使能GPIOB时钟 */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
/* 配置PB2和PB3为推挽输出 */
GPIO_InitStructure.GPIO_Pin = HSYNC_Pin | VSYNC_Pin;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
/* 设置同步信号为高电平 */
GPIO_SetBits(GPIOB, HSYNC_Pin);
GPIO_SetBits(GPIOB, VSYNC_Pin);
}
void VGA_TIM_Configuration(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
/* 使能TIM4时钟 */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
/* 配置TIM4为向上计数模式 */
TIM_TimeBaseStructure.TIM_Period = 65535;
TIM_TimeBaseStructure.TIM_Prescaler = (SystemCoreClock / PIXEL_CLK_FREQ) - 1;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);
/* 配置通道1为PWM模式1 */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = (PIXEL_CLK_FREQ / H_PIXEL_FREQ) / 2;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OC1Init(TIM4, &TIM_OCInitStructure);
/* 启动TIM4 */
TIM_Cmd(TIM4, ENABLE);
}
```
该程序的实现非常简单,只需要向GPIOB的PB2和PB3两个引脚输出同步信号即可。另外,还需要配置一个定时器来产生像素时钟信号,以便控制像素的输出时间。这里使用的是TIM4定时器,其时钟频率为25MHz,比VGA所需的像素时钟频率略高。因此,需要通过定时器的分频器来调整时钟频率,以确保像素时钟频率精确为25.175MHz。最后,需要将TIM4的通道1配置为PWM模式1,以产生像素时钟信号。
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