Diff: main.cpp

Revision:

2:6d472c554758

Parent:

1:dc799997391e

Child:

3:1a4ad4c82046

--- a/main.cpp	Mon Aug 06 17:24:16 2012 +0000
+++ b/main.cpp	Tue Aug 07 12:07:32 2012 +0000
@@ -9,6 +9,7 @@
 #include "mbed.h"
 
 DigitalOut adcCS(p8);
+DigitalOut cyc(p10);
 AnalogOut vca(p18);
 SPI adcSPI(p5,p6,p7); //talk to ad7921
 Serial pc(USBTX, USBRX);
@@ -19,21 +20,13 @@
 Ticker intTick;
 
 float pGain = 0.5;
-float iGain = 5000.;
-float integrator = 0; //the building up integrator value
-
-//for keeping track of the cycle rate
-float cycT=0;  
-float cycN=0;
+float iGain = 1000.;
+float integrator = 0.; //the building up integrator value
 
 void serialComm(){
     char c;
     float f;
     
-    pc.printf("Average cycle time [us]: %f\n",cycT/cycN);
-    cycT = 0;
-    cycN = 0;
-    
     if (pc.readable()) { 
         c = pc.getc();
         pc.scanf("%f", &f);
@@ -45,6 +38,8 @@
             case 'i':
                 iGain = f;   
                 pc.printf("Changed i gain to %f.\n",iGain);
+                if (f==0)
+                    integrator = 0.;
                 break;
             default:
                 pc.printf("Command not understood.\n",iGain);
@@ -58,48 +53,49 @@
     if (integrator > 3.3) {
             integrator = 3.3;
         }
-    if (integrator < -3.3) {
-        integrator = -3.3;
+    if (integrator < 0) {
+        integrator = 0;
     }
 }
 
 int main() {
-    float err=0.;
+    float err=0;
+    float out=0.;
     int ctl=0;
     int pd=0; 
     pc.printf("mbed restarted!\n");
     
-    adcSPI.format(16,3);
-    adcSPI.frequency(2000000); //2MHz
+    adcSPI.format(16,2);
+    adcSPI.frequency(5000000); 
     
-    //commTick.attach(&serialComm,0.5); //check serial every half second  
-    //intTick.attach(&limitIntegrator,0.001); //check integrator overrun every ms  
+    commTick.attach(&serialComm,0.5); //check serial every half second  
+    intTick.attach(&limitIntegrator,0.001); //check integrator overrun every ms  
     
     t.start();
-    
+    cyc = 0;    
 
     while(1) {
+        cyc = cyc ^ 1; //toggle debug pin
+        //read in from AD7921 over SPI
         adcCS = 0;
-        ctl = adcSPI.write(3<<13); //select ch 1
+        pd = adcSPI.write(3<<13); //select ch 1  
+        pd = (pd) & 0xFFF;
         adcCS = 1;
-        wait_us(20);
+        
         adcCS = 0;
-        pd = adcSPI.write(1);       // select ch 0
+        ctl = adcSPI.write(1);       // select ch 0
         //take the last 12 bits that carry data
-        // for some reason, it seems shifted up by one...
-        pd = (pd>>1) & 0xFFF;
-        ctl = (ctl>>1) & 0xFFF;
-        pc.printf("Read %i from V0 and %i from V1.\n",ctl,pd);
-        adcCS = 1;
-        wait_ms(100);
-       /* err = ctl.read() - pd.read();  
-        cycT += t.read_us();
-        cycN += 1.;
-        integrator += err * iGain * t.read_us(); 
+        ctl = (ctl) & 0xFFF;    
+        adcCS = 1;  
+              
+        err = ctl*3.3/4095. - pd*3.3/4095.; //convert to volt   
+        integrator += err * iGain*1.e-6 * t.read_us(); 
         t.reset(); //reset timer to get next integration time 
              
-        vca = err * pGain + integrator;        //analog output
+        out = 1.0* err * pGain + integrator;        //analog output
+        vca.write(out); 
         
-        */
+        //  pc.printf("Measuring ctl=%i and pd=%i, err=%f, vca is %f\n",ctl,pd,err,out);
+        
     }
 }