【Beagle Bone开源设计】PWM驱动四旋翼电调

2万 · 2015-1-12 21:22

本帖最后由 hudi008 于 2015-1-12 23:18 编辑

无刷电机的电调驱动很简单，就是一个PWM信号，50HZ，电机转速大小跟脉冲宽度有关。

0.5-2.5ms，一般都是1.1-1.9ms。如下图。

Beagle Bone 有好多个PWM引脚。

先来做一个试试看效果，用C语言实现。。
先来看看效果。

测试了一个50Hz的信号。

看代码：

用的宏定义，大家一看就能明白，
而且有注释，
欢迎大家讨论。

#include <stdlib.h> 

#include <stdio.h> 

#include <string.h> 

#include <fcntl.h> 

#define SLOT_DIR "/sys/devices/bone_capemgr.9/slots" 

#define PWM1_DIR "/sys/bus/platform/drivers/pwm_test/pwm_test_P8_13.15"

#define PWM1_duty "/sys/bus/platform/drivers/pwm_test/pwm_test_P8_13.15/duty"

#define PWM1_period "/sys/bus/platform/drivers/pwm_test/pwm_test_P8_13.15/period"

#define PWM1_run "/sys/bus/platform/drivers/pwm_test/pwm_test_P8_13.15/run"

#define MAX_BUF 80



void main() 

{ 

int fd, len; 

char buf[MAX_BUF]; 

char ch; 

int i; 

FILE *stream=NULL;

//Cofig P8.13 PWM

fd = open(SLOT_DIR, O_WRONLY); 

len = snprintf(buf,sizeof(buf),"bone_pwm_P8_13"); 

write(fd,buf,len); 

len = snprintf(buf,sizeof(buf),"am33xx_pwm"); 

write(fd,buf,len); 

close(fd); 

//Disable P8.13 PWM

fd = open(PWM1_run, O_WRONLY); 

len = snprintf(buf,sizeof(buf),"0");        

write(fd,buf,len); 

close(fd); 

//set period 20000000

fd = open(PWM1_period, O_WRONLY); 

len = snprintf(buf,sizeof(buf),"20000000"); 

write(fd,buf,len); 

close(fd); 

//set duty 20000000

fd = open(PWM1_duty, O_WRONLY); 

len = sprintf(buf,"%d",10000000);; 

write(fd,buf,len); 

close(fd); 

//Enable P8.13 PWM

fd = open(PWM1_run, O_WRONLY); 

len = snprintf(buf,sizeof(buf),"1");        

write(fd,buf,len); 

close(fd);





while(1)

{

for(i=0;i<10;i++)

{

//Disable P8.13 PWM

fd = open(PWM1_run, O_WRONLY); 

len = snprintf(buf,sizeof(buf),"0");        

write(fd,buf,len); 

close(fd); 

//set duty 

fd = open(PWM1_duty, O_WRONLY); 

len = sprintf(buf,"%d",1000000*i);; 

write(fd,buf,len); 

close(fd); 

//Enable P8.13 PWM

fd = open(PWM1_run, O_WRONLY); 

len = snprintf(buf,sizeof(buf),"1");        

write(fd,buf,len); 

close(fd);

usleep(1000000);

}

}

}