本帖最后由 740071911 于 2021-7-4 09:25 编辑
实现pwm呼吸灯效果
1、pwm功能添加，打开mcc，根据如下配置，设置pwm输出到RC1引脚。
2、代码编写。
因为pwm为12bit，所以每1ms增加1，到0~4095时间太长，观察效果不好，
改为1ms ，PWM占空比增加2，这样往复循环，4s左右的呼吸灯。
pwm函数介绍
- PWM1_16BIT_SetSlice1Output1DutyCycleRegister();//设置占空比
定时器中断函数- void TMR0_DefaultInterruptHandler(void){
- // add your TMR0 interrupt custom code
- // or set custom function using TMR0_SetInterruptHandler()
-
- static unsigned short int tmr_cnt = 0;
- static unsigned short int pwm_duty = 0;
- static unsigned char dir = 0;
-
- // clear the TMR0 interrupt flag
- PIR3bits.TMR0IF = 0;
- // Write to the Timer0 register
- TMR0H = timer0ReloadVal16bit >> 8;
- TMR0L = (uint8_t) timer0ReloadVal16bit;
-
- if (dir == 0) //increase duty
- {
- pwm_duty+=2;
- if (pwm_duty >= 4095)
- {
- pwm_duty =4095;
- dir = 1;
- }
- }
- else //decrease duty
- {
- pwm_duty -=2;
- if (pwm_duty > 60000)
- {
- pwm_duty = 0;
- dir = 0;
- }
- }
- PWM1_16BIT_SetSlice1Output1DutyCycleRegister(pwm_duty);
- PWM1_16BIT_LoadBufferRegisters();//使能占空比修改
- if(++tmr_cnt >= 1000)
- {
- tmr_cnt = 0;
- flag_1s = 1;
- //IO_RC1_Toggle();
- }
- }
3、完整代码
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