Diff: main.cpp

Revision:

0:c005165bbb7e

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun May 07 19:13:35 2017 +0000
@@ -0,0 +1,125 @@
+/* measure.cpp verion 1.0 */
+/* wajw  25/08/15  */
+
+/* Prog to measure period of rotation of flywheel */
+/* and display value on the Application Board LCD */
+/* Generates interrupt on +ve edge of CAP2.0 (mbed pin 30) and display capture regt */
+/* ISR Stores captured Timer2 value as 'period', resets Timer 2 and sets flag */
+
+/* For test purposes, a Ticker is producing pulses on pin 29,*/
+/* and these can be used to drive CAP2.0 on pin 30 */
+/* Ticker also drives LED1 which switches after 10 pulses as health check */
+
+/* To use the Ticker - need to join pins 29 and 30 */
+
+
+#include "mbed.h"
+#include "C12832_lcd.h"
+
+//Global Variables:
+
+volatile int count = 0, period = 0;
+volatile int pflag = 0, sflag = 0;
+C12832_LCD lcd;
+
+// Function Prototypes:
+
+void led_switch(void);  
+void Tick1_isr (void);
+void Timer2_isr (void);
+void Timer2_init (void);
+
+// Diagnostic Features:
+
+Ticker Tick; //Tick produces a periodic interrupt
+DigitalOut myled(LED1); //myled is diagnostic O/P driven by Ticker
+DigitalOut displed(LED2); //displed is diagnostic O/P driven by Timer2_isr()
+DigitalOut pulse(p29); //Pulse output for testing measure software
+
+//Function Declarations:
+
+void led_switch() 
+// Function which Toggles LED1 
+{ 
+    myled=!myled;
+}
+
+void Timer2_init()
+{
+// Connect pin 30 to CAP2.0:
+
+   LPC_PINCON->PINSEL0 |= (0x3<<8);    // Bits 9,8 = 1,1 = pin function CAP2.0 (p30)
+
+//Configure Timer 2:
+
+   LPC_SC->PCONP |= (0x01 << 22); // Enable Timer 2
+   LPC_SC->PCLKSEL1 |= (0x01 << 12) ; //Timer2 to use CCLK
+   LPC_TIM2->PR = 9600 - 1; //Set Timer2 prescale 
+   LPC_TIM2->TCR |= (0x01); //Enable Timer2
+   LPC_TIM2->CTCR |= (0x00); // Timer2 in timer mode
+   LPC_TIM2->TC = (0x00); //Initialise Timer2  
+   
+//Configure Capture input mode:
+
+   LPC_TIM2->CCR |= (0x01);  //Capture on +ve edge of CAP2.0
+   LPC_TIM2->CCR |= (0x01 << 2);  //Generate Interrupt on +ve edge CAP2.0
+}
+
+void T1_isr() 
+//ISR which flips the ulse O/P and sets sflag after 1 second
+{  
+    pulse = !pulse; //  flip the pulse O/P
+    count++; 
+    if (count >= 10) { 
+      count = 0;   //1 second has passed
+      sflag = 1;
+      }
+}
+
+void Timer2_isr()
+ //Interrupt caused by +ve pulse on CAP2.0
+ //Captured value = period 
+ 
+ {
+     if ((LPC_TIM2->IR & 0x10) != 0) {    //Check CAP2.0 Interrupt?
+         period = LPC_TIM2->CR0;        //save period
+         LPC_TIM2->TC = (0x00);         //Reset Timer2    
+         LPC_TIM2->IR = 0x10;           // clear CAP2.0 interrupt
+         displed = !displed;            //toggle diagnostic LED
+         pflag = 1;                     //New period available           
+         }
+ }
+ 
+ 
+int main()
+{ 
+
+   Timer2_init();
+   
+   Tick.attach_us(&T1_isr, 50000);   //initializes the ticker with period of 50msec
+                                  //and attaches it to T1 ISR
+
+
+//Associate Timer2_isr to Interrupt from Timer 2:
+
+   NVIC_SetVector(TIMER2_IRQn, (uint32_t)Timer2_isr); 
+   NVIC_EnableIRQ(TIMER2_IRQn); //Enable Interrupts on Timer 2
+
+  
+
+   lcd.cls();
+   lcd.locate(0,0);
+   lcd.printf("Period in Timer 2 Counts");
+    while(1) {
+        if (pflag == 1) // new data?
+        {        
+        lcd.locate(0,15);
+        lcd.printf("Period: %d", period); //display captured data
+        pflag = 0; //reset flag
+        }
+        if (sflag ==1){
+            led_switch(); //blink light
+            sflag = 0;
+            }
+        }
+}