Revision 4:cdcf29f5d75b, committed 2016-09-12

Comitter:

fkhan39

Date:

Mon Sep 12 21:18:43 2016 +0000

Parent:

2:f131a1777c54

Commit message:

watchdog timer

Changed in this revision

--- a/main.cpp	Mon Sep 12 20:53:25 2016 +0000
+++ b/main.cpp	Mon Sep 12 21:18:43 2016 +0000
@@ -19,9 +19,43 @@
 PwmOut rgb_b(p22);
 PwmOut rgb_r(p23);
 PwmOut rgb_g(p24);
+// WATCHDOG
+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
+ 
+// Simon's Watchdog code from
+// http://mbed.org/forum/mbed/topic/508/
+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;
+    }
+};
+Watchdog wdt;
 
 int main()
 {
+    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 10 second timeout on watchdog timer hardware
+// needs to be longer than worst case main loop exection time
+    wdt.kick(5.0);  
     // 2
     dip_switch1.mode(PullUp); // configure internal pull up resistor
     dip_switch2.mode(PullUp);
@@ -55,7 +89,11 @@
         chip.write(PORT_A, switch_state);
         wait(.2);
         // yellow led should change opposite the green led
-        
+        if (count == 12) while (1) {};
+        // LED 2 will stay on during the fault
+        count ++;
+        // End of main loop so "kick" to reset watchdog timer and avoid a reset
+        wdt.kick();
         // RGB led control
         rgb_r = control_pot;
         rgb_g = 0.5f - control_pot;