Diff: main.cpp

Revision:

1:159a09ac60ba

Parent:

0:5ce3cfc57999

Child:

2:c31a1758ac38

--- a/main.cpp	Sat Nov 21 13:24:29 2015 +0000
+++ b/main.cpp	Tue Feb 28 17:39:50 2017 +0000
@@ -1,52 +1,60 @@
 #include "mbed.h"
+#include "wdt.h"
 
-//WATHDOG ENABLED IN OUR KL25Z_SystemInit.c (overloading library function SystemInit.c)
-// It happens in this uC after reset watchdog is enabled with timeout=1024ms (2^10*LPO=1KHz)
-//  so mbed developers to allow a learning use of this board disable it on SystemInit.c
-// **BUT** SIM_COPC register can only be written once after reset and so it can not be enabled later
-//  I think best solution is to overload SystemInit() using:   void $Sub$$SystemInit (void) {
-//  original SystemInit() does not appear in export, it must be dowloaded from:
-// https://developer.mbed.org/users/mbed_official/code/mbed-src/file/a11c0372f0ba/targets/cmsis/TARGET_Freescale/TARGET_KLXX/TARGET_KL25Z/system_MKL25Z4.c
-//  you can arrive there from:
-// https://developer.mbed.org/handbook/mbed-SDK and https://developer.mbed.org/users/mbed_official/code/mbed-src/
+//WATCHDOG ENABLED (overloading library function SystemInit.c)
+// 
+// The KL25Z watchdog is enabled after reset with timeout=1024ms (2^10*LPO=1KHz)
+// To make the dvice easy to use on mbed, th watchdog is disabled at startup 
+// (in file SystemInit.c) **BUT** SIM_COPC register can only be written once 
+// after reset and so it can not be enabled later. To resolve this, 
+// SystemInit() is overloaded using:   void $Sub$$SystemInit (void) {
 //
-// MORE on this on: https://developer.mbed.org/users/chris/notebook/Patching-functions-and-libraries/
-// and searching "ARM Compiler toolchain Using the Linker" "Using $Super$$ and $Sub$$ to patch symbol definitions"
+// The original SystemInit() can be dowloaded from:
+//   https://developer.mbed.org/users/mbed_official/code/mbed-src/
+//   navigating to ... targets/cmsis/TARGET_Freescale/TARGET_KLXX/
+//                       TARGET_KL25Z/system_MKL25Z4.c
+//
+// MORE on how this overides the original initialisation: 
+//   https://developer.mbed.org/users/chris/notebook/Patching-functions-and-libraries/
+//   and searching "ARM Compiler toolchain Using the Linker" 
+//      "Using $Super$$ and $Sub$$ to patch symbol definitions"
 
-// Kick (feed, reload) our watchdog timer
-void wdt_kick(){
-    SIM->SRVCOP = (uint32_t)0x55u;
-    SIM->SRVCOP = (uint32_t)0xAAu;
-}
 
-// That set RED LED ON, do that first to evaluate boot time of peripherals
 #define LIGHT 0
 #define DARK 1
 DigitalOut led_red(LED_RED, LIGHT);
-DigitalOut led_green(LED_GREEN, DARK);
 DigitalOut led_blue(LED_BLUE, DARK);
 
-//Virtual serial port over USB using inboard second USB connector (USBKL25Z port)
-#include "USBSerial.h"
-//USBSerial pc;
-//...( vendor_id, product_id, product_release, connect_blocking )
-USBSerial pc( 0x1f00, 0x2012, 0x0001, false );
-//REMEMBER TO USE: class USBSerial -> connect_blocking = false (default is true)
-//  to avoid block of program when no USB cable connected in USBKL25Z port
-//NOTE: USBSerial still blocks program when closing serial terminal, that is fixed by our watchdog
-
+// Demonstate the watchdog
+//   The red LED is on after reset
+//   Th blue LED flashes and the watch dog is fed
+//   Aft 5sec, stop feeding the watchdog
+enum wState {Working, Stopped} ;
 
 int main(void) {
-    //to evaluate boot time I set led RED ON at the beginning of our main.cpp. TODO?: do it in SystemInit?
+    // initialise watchdog
+    wdt_1sec() ;
+    
+    // state of the watch dog
+    wState watchDog = Working ;
+    int counter = 10 ;
+    
+    // show start-up
     led_blue = DARK;
-    led_green = DARK;
+    led_red = LIGHT;
+    wait(0.5) ;
     led_red = DARK;
+    
+    // Note: the red LED now stays OFF until processor reset
     while(1)
     {
         led_blue = LIGHT;
-        pc.printf("I am a virtual serial port\r\n");    // THAT COULD BLOCK
-        wdt_kick();
+        wait(0.25);
+        if (watchDog == Working) wdt_kick_all() ;
         led_blue = DARK;
-        wait(0.5);
+        wait(0.25);
+        
+        // When the counter rachs zero, chang state to stop watchdog 
+        if (counter > 0) counter-- ; else watchDog = Stopped ;
     }
 }
\ No newline at end of file