main.cpp

00001 #include "mbed.h"
00002 Serial pc(USBTX, USBRX); // tx, rx
00003 DigitalOut led1(LED1);
00004 DigitalOut led2(LED2);
00005 DigitalOut led3(LED3);
00006 DigitalIn butt = (USER_BUTTON);
00007 
00008 DigitalOut CLK(PA_3);
00009 DigitalIn DATA(PD_7);
00010 
00011 int readSSI(DigitalOut CLK, DigitalIn DATA){
00012     int i,tmp,numBits = 13; 
00013     int angle = 0b00000000000000; //Initialise 13 bit 0 binary
00014     CLK=1; //Bring CLK high
00015     for(i =0;i<numBits;i++){
00016          CLK = 0;        
00017          wait_us(10);
00018          CLK =1;
00019          wait_us(10); //CLK cycle
00020          tmp = DATA.read(); 
00021          angle = angle<<1; //Shift previous read bits
00022          angle += tmp; //Add new bit
00023     }    
00024     wait_us(16); //Timeout 16us from datasheet
00025     CLK =0; 
00026     return angle;
00027 }
00028 
00029 
00030 int angle; 
00031  
00032 int main() {
00033     while(butt == 0){   //Startup readings
00034         led1 =!led1; 
00035         led2=!led2; 
00036         led3=!led3; 
00037         wait(0.1f);
00038     }
00039     wait(0.5f);
00040     printf("\r\n Start");
00041     
00042     while(1){
00043         printf("\r\n");
00044         CLK =0;
00045         angle = readSSI(CLK, DATA);
00046         printf("\r\n%d\r\n",angle);
00047         wait(.5f);
00048     }
00049 }
00050 
00051