Diff: main.cpp

Revision:

1:bac7ddc3679a

Parent:

0:9498eae934ed

--- a/main.cpp	Sat Feb 01 01:03:05 2014 +0000
+++ b/main.cpp	Sat Feb 01 15:52:15 2014 +0000
@@ -1,50 +1,66 @@
+/*
+For whatever reason the Watchdog timer cannot be made to work on a KL25Z using MBED.
+This example is based on Sw_reset by Peter Andersson.
+It uses a ticker routine that checks if random number generated in the main loop has not changed since the last ticker interrupt,
+an indication that the main loop has frozen. Once this condition is detected a pin, PTB10 in this example, is forced low.
+If this is linked to the opposite reset pin of the KL25Z be board will be restarted.
+
+*/
+
 #include "mbed.h"
 
-//DigitalOut led(LED1);
-DigitalOut  blueled  (LED_BLUE);
-DigitalOut  greenled (LED_GREEN);
-DigitalOut  redled   (LED_RED);
+void wd_check(void);                            //Define the watchdog check function "wd_check"
 
-Serial pc(USBTX,USBRX);
+Ticker watchdog;                                //Define a Ticker with the name "watchdog"
 
 
-int main() {
-    blueled = 1;                // Off
-    greenled = 1;               // Off
-    redled = 1;                 // Off
+//DigitalOut led(LED1);
+DigitalOut      blueled  (LED_BLUE);
+DigitalOut      greenled (LED_GREEN);
+DigitalOut      redled   (LED_RED);
+DigitalInOut    rst      (PTB10);               //Connect this to the reset pin
+
+Serial pc(USBTX,USBRX);                         //Send diagnostics via USB serrial port
 
-    SIM->COPC= 0x0C;            // Initialise Watchdog for 2^10 cycles of 1 KHz LPO clock ~ 1 second
-    // Use the Macro in 'MKL25Z4.h' to write to the COPC options field
-    // https://mbed.org/users/mbed_official/code/mbed-Freescale/file/3a8b2b3870fb/cmsis/KL25Z/MKL25Z4.h
-//    SIM_COPC_COPT(0x0C);        // Initialise Watchdog for 2^10 cycles of 1 KHz LPO clock ~ 1 second
-   
-    blueled = 0;                // turn on blue BEFORE we test comms
-    pc.printf("Hello World!\r\n");// Show that the code has started running at the beginning
-    blueled = 1;                // turn off Blue
-    greenled = 0;               // turn on  Green AFTER we tested comms
+int iHang;                                      //Hangup counter    
+int timeout;                                    //Main loop generated random number
+int timeout1;                                   //Previous randon number
 
-    int iHang = 0;              // Initialise our loop counter to Zero
+//Ticker interrupt code
+void wd_check()                                 //the function that Ticker will call
+{
+    blueled=!blueled;                           //toggle the blue LED
+    if (timeout1==timeout){                     //Is the new timeout randon number the same as the last
+        rst.output();                           //If so the main loop must have frozen
+        rst.write(0);                           //so force a hardware reset
+        }                                       //else 
+    timeout1=timeout;                           //Store current timeout as the old number ready for next interrupt
+}                                               //return
 
-    while(1) {                  // The start of the 'forever' main loop
-        pc.printf("loop %d\r\n", iHang);    // Show that we are looping
-        wait(0.1);              // wait .1 second
-        blueled = 0;            // turn on blue (as well as green) while we loop
-        
-        SIM->SRVCOP = 0x55;     // refresh the Watchdog to stop it resetting us
-        SIM->SRVCOP = 0xAA;
-        // Use the Macro in 'MKL25Z4.h' to write to the SRVCOP data field
-        // https://mbed.org/users/mbed_official/code/mbed-Freescale/file/3a8b2b3870fb/cmsis/KL25Z/MKL25Z4.h
-//        SIM_SRVCOP_SRVCOP(0x55);// refresh the Watchdog to stop it resetting us
-//        SIM_SRVCOP_SRVCOP(0xAA);
+//Main Program
+int main() {
+    greenled = 1;                               //Off
+    redled = 1;                                 //Off
+   
+    blueled = 0;                                //turn on blue BEFORE we test comms
+    pc.printf("Hello World!\r\n");              //Show that the code has started running at the beginning
+    greenled = 0;                               //turn on  Green AFTER we tested comms
+
+    watchdog.attach(&wd_check, 2);              //Initialise the ticker
+    
+    int iHang = 0;                              //Initialise our loop counter to Zero
 
-        iHang++;                // Count the number of times we have prevented a reboot
+    while(1) {                                  //The start of the 'forever' main loop
+        pc.printf("loop %d\r\n", iHang);        //Show that we are looping
+        wait(0.1);                              //wait .1 second
+        iHang++;                                //Count the number of times we have prevented a reboot
+        timeout== rand();                       //set timeout to a random number if this doesn't change then the program must have frozen
 
-        if(iHang == 10) {       // after 10 times round the loop...
-            blueled = 1;        // turn off Blue
-            greenled = 1;       // turn off Green
-            redled = 0;         // turn on  Red
-            while(1) ;          // Stall the program until the watchdog resets the micro'
+        if(iHang == 10) {                       //after 10 times round the loop...
+            blueled = 1;                        //turn off Blue
+            greenled = 1;                       //turn off Green
+            redled = 0;                         //turn on  Red
+            while(1) ;                          //Stall the program until the watchdog resets the micro'
         }
-
-    }                           // End of 'forever' loop
+    }                                           //End of 'forever' loop
 }