Rough PID added

workspace/ts100/inc/PID.h

@@ -0,0 +1,18 @@
+/*
+ * PID.h
+ *
+ *  Created on: 20 Sep 2016
+ *      Author: ralim
+ */
+
+#ifndef PID_H_
+#define PID_H_
+#include "Analog.h"
+#include "Interrupt.h"
+struct {
+	uint32_t kp, ki, kd; //PID values
+} pidSettings;
+
+int32_t computePID(uint16_t setpoint);
+void setupPID(void);
+#endif /* PID_H_ */

workspace/ts100/src/PID.c

@@ -0,0 +1,45 @@
+/*
+ * PID.c
+ *
+ *  Created on: 20 Sep 2016
+ *      Author: ralim
+ */
+
+#include "PID.h"
+#define MAXPIDOUTPUT 500000
+//This funtion computes the new value for the ON time of the system
+//This is the return value from this function
+int32_t computePID(uint16_t setpoint) {
+	static uint32_t lastSample = 0;
+	 int32_t ITerm = 0;
+	static int16_t lastReading = 0;
+	if (millis() - lastSample > 50) {
+		//only sample every 100 milliseconds
+		uint16_t currentReading = readIronTemp(0); //get the current temp of the iron
+		uint16_t error = setpoint - currentReading; //calculate the error term
+		ITerm += (pidSettings.ki * error);
+		if (ITerm > MAXPIDOUTPUT)
+			ITerm = MAXPIDOUTPUT;
+		else if (ITerm < 0)
+			ITerm = 0; //cap at 0 since we cant force the iron to cool itself :)
+
+		int16_t DInput = (currentReading - lastReading); //compute the input to the D term
+		int32_t output = (pidSettings.kp * error) + (ITerm)
+				- (pidSettings.kd * DInput);
+		if (output > MAXPIDOUTPUT)
+			output = MAXPIDOUTPUT;
+		else if (output < 0)
+			output = 0;
+		lastSample = millis();
+		lastReading = currentReading; //storing values for next iteration of the loop
+		return output;
+	}
+	return -1; //called too fast
+}
+
+void setupPID(void) {
+	pidSettings.kp = 15;
+	pidSettings.ki = 2;
+	pidSettings.kd = 1;
+
+}