STM32驱动vga显示彩条程序

以下是一个简单的基于STM32的VGA显示彩条程序，可以让你开始学习如何驱动VGA显示器。

#include "stm32f10x.h"
#include "stm32f10x_gpio.h"
#include "stm32f10x_rcc.h"
#include "stm32f10x_tim.h"

#define PIXELS_PER_LINE 800
#define PIXEL_CLOCK 25175000
#define VH_SYNC_WIDTH 96
#define VH_BACK_PORCH 48
#define VH_FRONT_PORCH 16

volatile uint16_t framebuffer[PIXELS_PER_LINE];

void init_vga_gpio(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB, ENABLE);
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_14 | GPIO_Pin_15;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9 | GPIO_Pin_10 |
                                  GPIO_Pin_11 | GPIO_Pin_12 | GPIO_Pin_13;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
}

void init_vga_timer(void)
{
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_TimeBaseStructure.TIM_Prescaler = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseStructure.TIM_Period = PIXELS_PER_LINE + VH_SYNC_WIDTH +
                                       VH_BACK_PORCH + VH_FRONT_PORCH;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
}

void init_vga_timer_interrupt(void)
{
    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
    TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
}

void TIM2_IRQHandler(void)
{
    static uint16_t line_counter = 0;
    static uint16_t pixel_counter = 0;
    static uint16_t color_counter = 0;
    static uint16_t red = 0;
    static uint16_t green = 0;
    static uint16_t blue = 0;
    if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET) {
        TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
        if (line_counter < 480) {
            if (pixel_counter < PIXELS_PER_LINE) {
                if (color_counter < 16) {
                    framebuffer[pixel_counter] = ((red & 0x1F) << 11) |
                                                 ((green & 0x3F) << 5) |
                                                  (blue & 0x1F);
                    color_counter++;
                } else {
                    color_counter = 0;
                    blue += 2;
                    if (blue > 31) {
                        blue = 0;
                        green += 4;
                        if (green > 63) {
                            green = 0;
                            red += 2;
                        }
                    }
                }
                pixel_counter++;
            } else {
                pixel_counter = 0;
                line_counter++;
            }
        } else {
            line_counter = 0;
            red = 0;
            green = 0;
            blue = 0;
        }
        TIM_SetCompare1(TIM2, pixel_counter + VH_SYNC_WIDTH +
                                    VH_BACK_PORCH + VH_FRONT_PORCH);
    }
}

int main(void)
{
    init_vga_gpio();
    init_vga_timer();
    init_vga_timer_interrupt();
    TIM_Cmd(TIM2, ENABLE);
    while (1) {
    }
}

这个程序使用了STM32的定时器和GPIO模块来生成VGA信号，并在显示器上显示彩条。程序中使用的是800x480像素的分辨率，每个像素使用16位颜色表示。在每个像素时钟周期中，程序会将当前颜色值写入framebuffer中，因此可以实现彩条的效果。