File content as of revision 0:58d3ade33116:

#include "mbed.h"

Serial motorDriver(PA_9, PA_10);
//Serial pc(PA_2, PA_3);


SPISlave spi(PA_7, PA_6, PA_5, PA_4);






Ticker loop;
int response1 = 0;

int count = 0;
int bytes[4];

int encoder = 0;
int current = 0;
int flag = 0;
int currentCmd = 0;
int currentCmdOld = 0;



void setCurrent(int current){
    wait_us(5);
    int tc;
    if (current<-2048){ current = -2048;}   //1800 = 60A = 27 Nm
    else if (current>2047){ current = 2047;}

    tc = current;
    char byte1 = 0x40+ ((tc&0xFFF)>>6);
    char  byte2 = tc&0x3F;

    motorDriver.putc(byte1);
    motorDriver.putc(byte2);
    
    //pc.printf("tc: %d   byte1: %d    byte2: %d\n\r", tc, byte1, byte2);
    
    }

void sendCmd(void){
    //motorDriver.putc(0x02);
    //motorDriver.putc(0x00);
    //motorDriver.putc(0x61);
    setCurrent(currentCmd);
    //pc.printf("%d\n\r", currentCmd);
    count = 1;
    }
    

    
void readSPI(void){
    //if(spi.receive()){
    wait_us(1);
    response1 = SPI1->DR;   // read response straight out of the register.  spi.read() breaks everything, not sure why.
    //printf('%d\n\r', currentCmd);
        spi.reply(encoder+28672);
        //printf("%d\n\r", response1);
        currentCmd = response1-32768;
        
        if(currentCmd < -2048){currentCmd = currentCmdOld;}     //throw away out-of-bounds values
        else if(currentCmd > 2048){currentCmd = currentCmdOld;}
        currentCmdOld = currentCmd;
        
        sendCmd();
        //pc.printf("%d\n\r", currentCmd);
   //   }
    }

 extern "C" void SPI1_IRQHandler(void)
{
    readSPI();

}
   
void echo(void){
    
    while(motorDriver.readable()){
    int byte = motorDriver.getc();
    //pc.putc(byte);
    if(count>0){
        bytes[count-1] = byte;
        if(count == 4){
             encoder = (bytes[0]<<5) + (bytes[1]>>3);
             current = ((bytes[1]&0x7)<<9) + (bytes[2]<<1) + (bytes[3]>>7);
             flag = bytes[3]&0x7F;
             count = 0;
             
             //pc.printf("  Encoder: %d    Current: %d    Flag:  %d\n\r",encoder, current, flag);
             }
        else{count++;}
        }

    //count++;
        }
    }
    
void transmit(void){
    //motorDriver.putc(pc.getc());
    }
  


void printStuff(void){
//    pc.printf("%d\n\r", currentCmd);

    }
    

    
int main() {
//    pc.baud(1000000);
//    pc.attach(&transmit);
//    pc.printf("SPI Dongle\n\r");
    
    
    spi.format(16, 0);
    spi.frequency(12000000);
    spi.reply(0x0);

    
    motorDriver.baud(1000000);
    motorDriver.attach(&echo);
    motorDriver.format(8, Serial::None, 2);
    wait(.1);
    motorDriver.putc(0x80);
    wait(.1);
    motorDriver.putc(0x6d);
    
    
    

    while(1) {

    readSPI();
    wait_us(50);
    //        }

     
    }
}