Diff: main.cpp

Revision:

0:09da8ea2d7a2

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Sep 25 20:14:40 2016 +0000
@@ -0,0 +1,86 @@
+#include "mbed.h"
+
+//DigitalIn Button1(p26); // Button = 1 when the button is not pushed
+//DigitalIn Button2(p25); // Button2 : the PWN pushbutton
+DigitalOut LED(p22); // normal LED
+//PwmOut LED(p22); // PWN object for LED
+
+
+// Part 1 Extra Credit Setup
+// LEDs used to indicate code activity and reset source
+DigitalOut myled1(LED1); //in main loop part 1
+DigitalOut myled2(LED2); //in main loop part 2 (where fault occurs)
+DigitalOut myled3(LED3); //The pushbutton or power on caused a reset
+DigitalOut myled4(LED4); //The watchdog timer caused a reset
+
+class Watchdog
+{
+public:
+// Load timeout value in watchdog timer and enable
+    void kick(float s) {
+        LPC_WDT->WDCLKSEL = 0x1;                // Set CLK src to PCLK
+        uint32_t clk = SystemCoreClock / 16;    // WD has a fixed /4 prescaler, PCLK default is /4
+        LPC_WDT->WDTC = s * (float)clk;
+        LPC_WDT->WDMOD = 0x3;                   // Enabled and Reset
+        kick();
+    }
+// "kick" or "feed" the dog - reset the watchdog timer
+// by writing this required bit pattern
+    void kick() {
+        LPC_WDT->WDFEED = 0xAA;
+        LPC_WDT->WDFEED = 0x55;
+    }
+};
+
+// Setup the watchdog timer
+Watchdog wdt;
+
+
+int main()
+{
+    // Part 1 - Extra Credit , Watchdog timer
+    int count = 0;
+// On reset, indicate a watchdog reset or a pushbutton reset on LED 4 or 3
+    if ((LPC_WDT->WDMOD >> 2) & 1)
+        myled4 = 1;
+    else myled3 = 1;
+
+// setup a 5 second timeout on watchdog timer hardware
+// needs to be longer than worst case main loop exection time
+    wdt.kick(8.0);
+
+// Main program loop - resets watchdog once each loop iteration
+// Would typically have a lot of code in loop with many calls
+    while (1) {
+        LED = 1; // LED is on 
+        wait(.05);
+        LED = 0; // LED is off
+        wait(.05);
+// Simulate a fault lock up with an infinite while loop, but only after 25 loop iterations
+        if (count == 5) while (1) {};
+// LED 2 will stay on during the fault
+        LED = 0;
+        count ++;
+// End of main loop so "kick" to reset watchdog timer and avoid a reset
+        wdt.kick();
+    }
+
+
+
+//    // Part 2 - PWN
+//    float dc = 0.5; // 50% duty cycle
+//
+//    LED.period(0.01f);      // 4 second period
+//    LED.write(dc);
+//
+//    while (1) {
+//        if (!Button1) {
+//            dc+=0.1;
+//            LED.write(dc);
+//        } else if (!Button2) {
+//            dc-=0.1;
+//            LED.write(dc);
+//        }
+//        wait(0.1);
+//    }
+}
\ No newline at end of file