请教：关于精英板 2.8寸屏背光调节的问题

抽屉里的吖牛 · 发表于 2021-10-28 11:51:25

对BL脚配置之后，背光无反应，不知道是哪里不对，想请教下。

下面分别是  pwm配置  和main.c的内容
//timer.c
void TIM3_PWM_Init(u16 arr,u16 psc)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //使能定时器3时钟
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB , ENABLE);  //使能GPIO外设和AFIO复用功能模块时钟

GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射  TIM3_CH2->PB5

//设置该引脚为复用输出功能,输出TIM3 CH2的PWM脉冲波形 GPIOB.0
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0; //TIM_CH2
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  //复用推挽输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化GPIO

//初始化TIM3
TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值
TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值
TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM向上计数模式
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位

//初始化TIM3 Channel2 PWM模式
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //选择定时器模式:TIM脉冲宽度调制模式2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高
TIM_OC2Init(TIM3, &TIM_OCInitStructure);  //根据T指定的参数初始化外设TIM3 OC2

TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);  //使能TIM3在CCR2上的预装载寄存器

TIM_Cmd(TIM3, ENABLE);  //使能TIM3

}

//main.c
int main(void)
{
u16 led0pwmval=0;
u8 dir=1;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);    //设置NVIC中断分组2:2位抢占优先级，2位响应优先级
delay_init();            //延时函数初始化
UART_Init(115200);    //串口初始化为115200

LED_Init();       //LED端口初始化
TIM3_PWM_Init(899,0);    //不分频。PWM频率=72000000/900=80Khz
//TIM3_Int_Init(4999,7200);
LCD_Init();
POINT_COLOR=RED;
LCD_Clear(WHITE);
LCD_ShowString(30,40,210,24,24,"WarShip STM32 ^_^");
LCD_ShowString(30,70,200,16,16,"TFTLCD TEST");

   while(1)
{

delay_ms(10);
if(dir)led0pwmval++;
else led0pwmval--;

if(led0pwmval>300)dir=0;
if(led0pwmval==0)dir=1;
TIM_SetCompare2(TIM3,led0pwmval);
}


}

请大家指点一番！！