File content as of revision 0:5b4f19f8cd85:

// Send a byte to a SPI slave, and record the response

#include "mbed.h"
#include "as5047.h"
#include <string> 
#include <sstream>

// software ssel
SPI motor_encoder(D11, D12, D13); // mosi, miso, sclk
DigitalOut motor_encoder_cs(D3); // ssel
DigitalOut motor_dir(D2); // ssel
Serial pc(SERIAL_TX, SERIAL_RX);
MotorType Motor;
Ticker PIDInterrupt;  //PID中断 500Hz

void PIDInterruptIRQ(); 


int main() 
{
    string UartBuf = "";
    char temp = 0;
    StepMotorInit(&Motor, &motor_dir, &motor_encoder_cs, &motor_encoder);
    Encoder_Init(&Motor);
    PIDInterrupt.attach(&PIDInterruptIRQ, 0.002);
    Motor.Goal = 5000;
    while(1)
    {
        if(pc.readable())
        {
            temp = pc.getc();
            if((temp != 'i') && (temp != ';') && ((temp < '0') || (temp > '9')))   //收到的非法字符
                continue;
            else if(temp == 'i')  //请求信息
                pc.printf("Position : %d, PWM Freq : %d, Goal : %d\r\n", Motor.Encoder, Motor.PIDControl, Motor.Goal);
            else if((temp >= '0') && (temp <= '9'))  //收到0-9
                UartBuf = UartBuf + temp;
            else  //收到 ;
            {
                Motor.Goal = atoi(UartBuf.c_str());
                pc.printf("Goal is set at %d\r\n", Motor.Goal);
                UartBuf = "";
            }
        }
        //pc.printf("Angle : %d, PID Value : %d, Difference : %d\r\n", Motor.Encoder, Motor.PIDControl, Motor.Difference);
    }
}

void PIDInterruptIRQ()  //PID中断服务函数
{   
    //缓存上一次的编码器读数
    Motor.EncoderPre = Motor.Encoder;
    //更新编码器读数
    Motor.Encoder = Encoder_ReadData(&Motor);
    //对编码器读数低通滤波 当快过零点的时候不能滤波，过零点时的编码器数据突变会干扰滤波值
    if((Motor.Encoder <= 16200) && (Motor.Encoder >= 100))
        Motor.Encoder = Fliter_1(Motor.Encoder, Motor.EncoderPre);
    //速度-位置环PID控制
    MotorPIDController(&Motor);
    //更新脉冲频率
    StepMotorSetFreq(&Motor);
}