Diff: main.cpp

Revision:

0:d4187a097285

Child:

1:2d9d931c8484

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Dec 28 13:29:12 2016 +0000
@@ -0,0 +1,135 @@
+#include "mbed.h"
+
+#define TMD2772_Addr 0x72 //this is the 8-bit address
+const uint8_t ALSDataRegister = 0x14;
+const uint8_t waitIntervals = 100; //number of 2.73 ms waits
+const int measPeriod_ms = 699;
+
+
+I2C i2c(I2C_SDA,I2C_SCL);
+Serial pc(USBTX,USBRX); //open serial port (optionally add baud rate after specifying TX and RX pins)
+Timer t;
+PwmOut mypwm(PA_1);
+
+void writeRegister(uint8_t addr, uint8_t reg, uint8_t val) {
+ /*writes 1 byte to a single register*/
+    char writeData[2];
+    writeData[0] = reg | 0x80;
+    writeData[1] = val;
+    i2c.write(addr,writeData, 2);
+}
+
+void writeBlock(uint8_t addr, uint8_t startReg, uint8_t *data, uint8_t numBytes) {
+/*writes data from an array beginning at the startReg*/
+    char writeData[numBytes+1];
+    writeData[0]=startReg | 0x80;
+    for(int n=1;n<numBytes;n++) {
+        writeData[n]=data[n-1];
+    }
+    i2c.write(addr,writeData,numBytes+1);
+}
+
+void readBlock(uint8_t addr, uint8_t startReg, char *data, int numBytes) {
+    char writeData = startReg | 0x80;
+    i2c.write(addr,&writeData,1,true);
+    i2c.read(addr,data,numBytes);
+}
+
+uint16_t LSB_MSB_2uint16(char *data) {
+/*returns an unsinged 16 bit integer from a 2 data bytes, where the second byte is the MSB*/
+    return ((uint16_t)data[1] << 8) + (uint16_t)data[0];
+}
+
+void regDump(uint8_t Addr, uint8_t startByte, uint8_t endByte) {
+/*print the values of up to 20 registers*/
+    char regData[20];
+    int numBytes;
+    if (endByte>=startByte) {
+        numBytes =  (endByte-startByte+1) < 20 ? (endByte-startByte+1) : 20;
+    }
+    else {
+        numBytes=1;
+    }    
+        
+    regData[0] = startByte | 0x80;
+    i2c.write(TMD2772_Addr,regData,1,true);
+    i2c.read(TMD2772_Addr, regData, numBytes);
+    for(int n=0;n<numBytes;n++) {
+      pc.printf("%X \r\n", regData[n]);
+    }
+}
+
+
+
+void initTMD2772(void) {
+    writeRegister(TMD2772_Addr,0x00,0x0B);// Set power on, ALS enabled, Wait enabled, Interrupts enabled (register 0)
+    writeRegister(TMD2772_Addr,0x01,0x00);//ALS time register - 0x00 is max integration time of 699ms (register 1) 
+    writeRegister(TMD2772_Addr,0x03,0xFF-waitIntervals); // Wtime = 2.73 ms * delay peroids (subtract from 0xFF to enter into register)
+    writeRegister(TMD2772_Addr,0x0D,0x04); //optionally scale ALS gain by 0.16 by seleting 0x04;
+//    writeRegister(TMD2772_Addr,0x0D,0x00); //optionally scale ALS gain by 0.16 by seleting 0x04;
+
+    writeRegister(TMD2772_Addr,0x0F,0x00); //ALS gain is 1x
+}
+
+int main() {
+    float ratio;
+    char data[4];
+    uint16_t ch0Data;
+    uint16_t ch1Data;
+    char reg2write;
+    float setpoint = 29500;
+    float step = 0.0001; //duty cycle change per sample
+    float dutyCycle=0.88;
+    float dutyCycleMin =0.8;
+    float dutyCycleMax =0.99;
+    float pGain = 0.25;
+    float err;
+    float tol=2.5;
+    
+    //setup everything
+    mypwm.period_ms(5);
+    mypwm.write(dutyCycle);
+    i2c.frequency(400000); //set I2C frequency to 400kHz
+    wait_ms(1000);
+    initTMD2772();
+    regDump(TMD2772_Addr,0x00,0x0F);
+    pc.printf("Done initializing\r\n");
+    wait_ms(700);
+    
+    //get initial filter value
+    reg2write=ALSDataRegister | 0x80;
+    i2c.write(TMD2772_Addr,&reg2write,1,true); //1 byte of data, repeated start for read
+    i2c.read(TMD2772_Addr,data,4);
+    ch0Data = LSB_MSB_2uint16(data);
+    ch1Data = LSB_MSB_2uint16(data+2);
+    ratio = (float)ch0Data/(float)ch1Data;
+    wait_ms(699);
+    
+    while(1) {
+        t.start();
+        reg2write=ALSDataRegister | 0x80;
+//        pc.printf("%X\r\n",reg2write);
+        i2c.write(TMD2772_Addr,&reg2write,1,true); //1 byte of data, repeated start for read
+        i2c.read(TMD2772_Addr,data,4);
+        ch0Data = LSB_MSB_2uint16(data);
+        ch1Data = LSB_MSB_2uint16(data+2);
+        ratio = (float)ch0Data/(float)ch1Data;
+        err = ch0Data - setpoint;
+        pc.printf( "%U,%U, %f, %f, %f\r\n",ch0Data,ch1Data,ratio, dutyCycle, mypwm.read());
+        if (abs(err)>tol) {
+            step = (ch0Data-setpoint)/setpoint * pGain;
+            dutyCycle -=step;
+            dutyCycle = (dutyCycle < dutyCycleMin) ? dutyCycleMin : dutyCycle;
+            dutyCycle = (dutyCycle > dutyCycleMax) ? dutyCycleMax : dutyCycle;
+            //update with new settings
+            mypwm.write(dutyCycle);
+        }
+        while(t.read_ms() < measPeriod_ms) {
+         //pc.printf("%U \r\n",t.read_ms());   
+        }
+        t.reset();
+    }
+    
+    
+}
+