Diff: main.cpp

Revision:

0:2c6d81be69d8

Child:

1:ab3dacbfcde6

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Jan 12 09:22:44 2018 +0000
@@ -0,0 +1,254 @@
+#include "mbed.h"
+
+#define M_PI 3.14159265358979323846
+
+//mbed class def
+Serial pc(USBTX, USBRX); // tx, rx
+SPI spi(p5, p6, p7); // mosi, miso, sclk
+DigitalOut cs(p8);
+
+PwmOut motorOn(p26);
+
+Timer t;
+
+//variable instaniation
+unsigned short calData[6];
+
+char buffer16[3];
+short int serbuffer[2]; 
+
+char tempBuffer[4];
+unsigned int temp = 0;
+char pressBuffer[4];
+unsigned int press = 0;
+
+unsigned int pData[1000];
+float spData[1000];
+unsigned int tData[1000];
+
+const char cb1 = 0xA2;
+const char cb2 = 0xA4;
+const char cb3 = 0xA6;
+const char cb4 = 0xA8;
+const char cb5 = 0xAA;
+const char cb6 = 0xAC;
+
+const char * commarr[6] = {&cb1, &cb2, &cb3, &cb4, &cb5, &cb6};
+
+const char D1conv256 = 0x40;
+const char D1conv512 = 0x42;
+const char D2conv4096 = 0x58;
+const char D2conv512 = 0x52;
+const char readADC = 0x00;
+
+float duty = 1;
+
+int round(float number)
+{
+    return (number >= 0) ? (int)(number + 0.5) : (int)(number - 0.5);
+}
+
+//calculate temperature
+int calcT(unsigned int Tval, unsigned short consts[6]) {
+    int dT = Tval - consts[4]*(2<<7);
+    
+    int T = 2000 + dT*consts[5]/(2<<22);
+    printf("Temp %d C\n\r", T); 
+    return T;
+    }
+
+//calculate 1st order temperature compensated pressure
+int calcP(unsigned int Tval, unsigned int Pval, unsigned short consts[6]) {
+    int dT = Tval - consts[4]*(2<<7);
+    
+    long long int off = (long long)consts[1]*(2<<16) + ((long long)consts[3] *(long long)dT)/(2<<5);
+    
+    long long int sens = (long long)consts[0]*(2<<15) + ((long long)consts[2] *(long long)dT)/(2<<6);
+    
+    int P = (Pval *(sens/(2<<20)) - off)/(2<<14);
+    //printf("Pressure %d Pa\n\r", P); 
+    return P;
+    }
+ 
+int main() {
+    pc.baud(115200);
+    motorOn = 0;
+    motorOn.period_ms(10);
+    
+    // Chip must be deselected
+    cs = 1;
+
+    // Setup the spi for 8 bit data, high steady state clock,
+    // second edge capture, with a 1MHz clock rate
+    spi.format(8,3);
+    spi.frequency(500000);
+    spi.set_default_write_value(0x00);
+ 
+    // Select the device by seting chip select low
+    cs = 0;
+ 
+    // Send 0x1E Command to reset the chip
+    spi.write(0x1E);
+    cs = 1;
+    wait_ms(100);
+    cs =1;
+    
+    //read cal data values from device into program
+    for (char i=0; i<6; i++){
+        //spi read sequence
+        cs= 0;
+        spi.write(commarr[i], 1, buffer16, 3);
+        //time for SPI to write into data buffers
+        wait_ms(10);
+        cs=1;
+        //Put data into 16bit unsigned int in calData array
+        calData[i] = buffer16[1]<<8 | buffer16[2];        
+        }
+        
+    //display calibration values to check against datasheet
+    printf("C1: %hu\n\rC2: %hu\n\rC3: %hu\n\rC4: %hu\n\rC5: %hu\n\rC6: %hu\n\r", calData[0], calData[1], calData[2], calData[3], calData[4], calData[5]);
+    
+    //program loop
+    while(1){
+        //read temerature value
+        cs = 0;
+        spi.write(&D2conv4096, 1, buffer16, 1);
+        wait_ms(10);
+        cs = 1; cs = 0;
+        
+        spi.write(&readADC, 1, tempBuffer, 4);
+        cs = 1;
+        
+        //read pressure value
+        cs = 0;
+        spi.write(&D1conv512, 1, buffer16, 1);
+        wait_ms(2);
+        cs = 1; cs = 0;
+        
+        spi.write(&readADC, 1, pressBuffer, 4);
+        cs = 1;
+        
+        //write values from buffers to program variables
+        temp = tempBuffer[1]<<16 | tempBuffer[2]<<8 | tempBuffer[3];
+        press = pressBuffer[1]<<16 | pressBuffer[2]<<8 | pressBuffer[3];
+        
+        //turn pump on
+        motorOn.write(duty);
+        
+        //dummy samples to wait for sensor response to stabilise
+        int a =0;
+        while(a<10000) {
+            cs = 0;
+            spi.write(&D1conv256, 1, buffer16, 1);
+            wait_us(500);
+            cs = 1; cs = 0;
+            spi.write(&readADC, 1, pressBuffer, 4);
+            cs = 1;
+            a++;
+            }
+            
+        
+        int nsample = 1000;
+        double cumsum = 0;
+        
+        t.reset();
+        t.start();
+        //loop values
+        for (int x=0; x <nsample; x++){
+           
+            cs = 0;
+            spi.write(&D1conv256, 1, buffer16, 1);
+            
+            wait_us(500);
+            cs = 1; cs = 0;
+            if (x >0){
+                pData[x-1] = pressBuffer[1]<<16 | pressBuffer[2]<<8 | pressBuffer[3];
+                cumsum = cumsum + pData[x-1];
+                }
+            spi.write(&readADC, 1, pressBuffer, 4);
+            tData[x] = t.read_us();
+            cs = 1;
+        
+            }
+            
+        //stop motor and timer
+        t.stop();
+        motorOn.write(0);
+        
+        //calc temperature
+        calcT(temp, calData);
+        long long sum = 0;
+        
+        float avg = calcP(temp, cumsum/(nsample-1), calData);
+        
+        printf("avg %f\n\r", avg); 
+        
+        //for crossing detection
+        bool cflag1 = (avg > pData[0]);
+        bool cflag2 = (avg > pData[1]);
+        int numcross = 0;
+        int lastcrosspoint = 0;
+        unsigned int crosstart;
+        unsigned int crossend;
+        float freq = 0;
+        
+        //smooth data array 20 sample size
+        for (int y=0; y< nsample-1; y++){
+            if (9< y && y <nsample-10){
+                sum = 0;
+                for (int z=0; z<20; z++){
+                    sum = sum + pData[y-10+z];
+                    }
+                    
+                spData[y] = (float) calcP(temp, sum/20, calData);
+                
+                //detect avg crossings for frequency calc
+                if (y>10){
+                    cflag2 = (avg > spData[y]);
+                    cflag1 = (avg > spData[y-1]);
+                    
+                    if (cflag1 != cflag2){
+                        if(lastcrosspoint<=(y-10)){
+                            numcross++;
+                            lastcrosspoint = y;
+                            
+                            if (numcross == 1){
+                                crosstart = tData[y];
+                                }
+                                
+                            crossend = tData[y];
+                            }
+                        }   
+                    }      
+                //calc pressure & display list
+                //printf("%d\t%d\t%d\n\r", tData[y], calcP(temp, spData[y], calData), calcP(temp, pData[y], calData));
+                printf("%d\t%f\n\r", tData[y],spData[y]);
+                } else if (10> y || y >nsample-10) {
+                    spData[y] = (float) calcP(temp, pData[y], calData);
+                    }
+            
+            
+            }
+        
+        printf("numcross = %d\n\r", numcross);
+        printf("crosstart = %d\n\r", crosstart);
+        printf("crossend = %d\n\r", crossend);
+            
+        freq = (1e6 *numcross)/(2*(crossend - crosstart));
+        printf("frequency = %f\n\r", freq);
+        
+        for (int z=0; z< nsample-1; z++){
+            
+            spData[z] = spData[z] -avg;
+            }
+        
+        printf("Repeat Blockage Test?\n\rPress Enter to continue\n\r");
+        
+        while(1){             
+            if (pc.getc() != 0) {
+                break;
+                }
+            }
+            
+        }
+}
\ No newline at end of file