Diff: main.cpp

Revision:

2:9ff654aaf923

Parent:

1:e86fb31f7e95

Child:

3:c89c3fa9395f

--- a/main.cpp	Wed Dec 02 12:34:53 2020 +0000
+++ b/main.cpp	Thu Jan 14 17:41:11 2021 +0000
@@ -1,10 +1,13 @@
+/* Konstantinos Fane
+ * kf289@kent.ac.uk
+ * ID: 20901830
+ */
 
 /* timing.cpp api verion 1.01 */
 /* wajw  21/03/18  */
 //V 1.02 mod to just do period measurement edh 24/03/18
 /* Prog to measure period of rotation of flywheel */
 
-
 /* Software uses Pin 9 as an interrupt to determine rotation period */
 /* A ticker is used to give a count of elapsed time */
 
@@ -15,47 +18,54 @@
 #include "C12832_lcd.h"
 #define counts_per_min 600000 // .1ms clock = 600k pulses minute
 
-//advance degree and RPM data arrays 
-static int map[] = {5,5,6,10,15,15,21,25,27,34,38}; // advance angles in degrees BTDC
-static int rpm_range[] = {500,600,700,800,900,1000,1100,1200,1300,1400,1500}; //rpm range for which the advance angle should change 
+// Advance degree and RPM data arrays:
 
-//Global Variables:
+// advance angles in degrees BTDC 
+static int map[] = {5,5,6,10,15,15,21,25,27,34,38};
+// rpm range for which the advance angle should change 
+static int rpm_range[] = {500,600,700,800,900,1000,1100,1200,1300,1400,1500};
 
-volatile int  period = 0, count1 = 0; //this was changed to float to display the period more precisely
+// Global Variables:
 
+volatile int  period = 0, count1 = 0;
 volatile int pflag = 0, rpm = 0;
 
-int lag;
-int spark_advance; //to be used for the advance degree input
+// Student added global variables:
+
+int lag;                // to be used to calculate the ignition lag
+int spark_advance;      // to be used for the advance degree input
 
 C12832_LCD lcd;
 
 // Function Prototypes:
 
-void Tick1_isr (void);
-void TDC_isr (void);
-void Spark_on (void); // set the output Spark (p10) high
-void Spark_off (void); // set it low
-void Ignition(int);
+void Tick1_isr (void);  // ISR for Ticker interrupt
+void TDC_isr (void);    // ISR for rising edge of TDC interrupt
+void Spark_on (void);   // set the output Spark (p10) high
+void Spark_off (void);  // set it low
+void Ignition(int); 
 
-//custom function prototypes
+// Custom function prototypes:
+
 void advance_calculator(int);
 
 
 // Hardware Definitions:
 
-Ticker Tick; //Tick produces a periodic interrupt
-DigitalOut Spark(p10);  //Spark Output to Flywheel Board
-InterruptIn tdc(p9);    //Pulse from TDC Sensor on Flywheel Board
+Ticker Tick;            // Tick produces a periodic interrupt
+DigitalOut Spark(p10);  // Spark Output to Flywheel Board
+InterruptIn tdc(p9);    // Pulse from TDC Sensor on Flywheel Board
 
-Timeout StartSpark; //one-off interrupt to set spark o/p high
-Timeout EndSpark; // and this one sets spark low
+Timeout StartSpark;     // one-off interrupt to set spark o/p high
+Timeout EndSpark;       // and this one sets spark low
 
-//Function Declarations:
+// Function Declarations:
+
+// triggers ignition spark based on the current advance angle provided
 void Ignition(int lag)
 {
-    StartSpark.attach_us(&Spark_on, lag) ; // set time of Spark
-    EndSpark.attach_us(&Spark_off, lag + 200); //and duration of spark at 200usec
+    StartSpark.attach_us(&Spark_on, lag) ;      // set time of Spark 
+    EndSpark.attach_us(&Spark_off, lag + 200);  // set spark duration at 200usec
 }
     
 void Spark_on()
@@ -68,28 +78,32 @@
     Spark = 0;
 }
 
-
+/* Interrupt cause by Ticker
+ * Increments count every 100usec
+ */
 void Tick1_isr()
-//Interrupt cause by Ticker
-//Increments count every 100usec
 {
      count1++;   
 }
 
+/* Interrupt caused by +ve edge on TDC 
+ * Captured value = period
+ */
 void TDC_isr()
- //Interrupt caused by +ve edge on TDC 
- //Captured value = period 
 {
-    period = count1;    //Capture time since last TDC
+    period = count1;    // Capture time since last TDC
     count1 = 0;
-    pflag = 1;         // New value of period available
+    pflag = 1;          // New value of period available
 }
 
-//custom functions declaration
+//Custom functions declaration:
+
+/* calculates the advance angle */
 void advance_calculator(int rpm)
 {
     if(rpm < rpm_range[0])
     {
+        // advance angle for any speeds lower than 500 RPM
         spark_advance = 360 - map[0];
     }
     else if(rpm >= rpm_range[0] && rpm < rpm_range[1])
@@ -132,8 +146,9 @@
     {
         spark_advance = 360 - map[9];
     }
-    else //this computes the angle for any speeds higher than 1500RPM (still same angle as 1500RPM)
+    else 
     {
+        // advance angle for speeds higher than 1500RPM(same angle as 1500RPM)
         spark_advance = 360 - map[10];
     }
 }
@@ -142,41 +157,58 @@
 int main()
 { 
 
-//Produce regular clock tick for timing period:
-  Tick.attach_us(&Tick1_isr, 100);   //initializes the ticker with period of 100usec
-                                  //and attaches it to Tick1 ISR 
+    /* Produce regular clock tick for timing period:
+     * initializes the ticker with period of 100usec
+     * and attaches it to Tick1 ISR
+     */
+    Tick.attach_us(&Tick1_isr, 100);
 
-   tdc.rise(&TDC_isr); // Generate Interrupt on each TDC pulse
-   
-   //ance_calculator(rpm); //called for the first time, since rpm is 0, 5 will be assigned to advance angle
-      
-    while(1) {
+    tdc.rise(&TDC_isr); // Generate Interrupt on each TDC pulse
+     
+    while(1) 
+    {
        
-       
-        //spark_advance = 360 - 15; //360(TDC point) - advance angle = spark_advance
+       // spark advance calculation = TDC point(360) - desired advance angle 
+       //spark_advance = 360 - 15;
+        
+       // function to calculate the spark advance for variating RPM speeds
        advance_calculator(rpm);
        
-       if (pflag == 1) // new timing data?
-        {  
-            //lag = (period*100)*180/360; // Period is in units of 100usec
-            lag = (period*100)*spark_advance/360; // Period is in units of 100usec
-            Ignition(lag);
+       // checks if new timing data is available
+       if (pflag == 1)
+       {  
+            //lag = (period*100)*180/360; // Period in units of 100usec
+            lag = (period*100)*spark_advance/360; // Period in units of 100usec
+            Ignition(lag); //triggers ignition spark for given advance angle
             
-            //your code here to calculate rpm
-            rpm = (1/(period*100e-6))*60; //1 period = 1*100us(period counter incrments every 100us, this conversion is needed to get the Hz frequency
+            /* RPM calculation command
+             * RPM = f(Hz) * 60 = (1/T() * 60
+             * 1 period = 1*100us(period counter incrments every 100us, 
+             * this conversion is needed to get the Hz frequency
+             */
+            rpm = (1/(period*100e-6))*60;
             
-            lcd.cls(); //this was moved in the while to refresh the screen at every itteration
+            /* "lcd.cls();" was moved inside the while()
+             * to fix a bug in the display, by refreshing
+             * the screen at every itteration
+             */
+            lcd.cls();
+            
+            // divided by 10 to display captured period same as the osciloscope
             lcd.locate(0,0);
-            lcd.printf("Period(T): %4.2d ms", period/10); // display captured data in ms to match the osciloscope reading 
+            lcd.printf("Period(T): %4.2d ms", period/10); 
+            
+            // display the captured RPM 
             lcd.locate(0,11);
-            lcd.printf("Speed(RPM): %4.2d ", rpm); // display captured data  
+            lcd.printf("Speed(RPM): %4.2d ", rpm); 
             
-            //this is used to print the advance angle for troubleshooting purposes
+            // display the advance angle for troubleshooting purposes
+            // 360 - spark advance = advance angle in BTDC (reverse operation)
             lcd.locate(0,22);
-            lcd.printf("Advance(deg): %4.2d ", 360-spark_advance); // display captured data  
+            lcd.printf("Advance(deg): %4.2d ", 360-spark_advance);
             pflag = 0; //reset flag 
         }
-        
+         
     }
 }