Revision 0:fc62d045ca0c, committed 2013-12-20

Comitter:

loopsva

Date:

Fri Dec 20 19:42:32 2013 +0000

Commit message:

Initial cut. A Watchdog timer for the LPC4088.

Changed in this revision

diff -r 000000000000 -r fc62d045ca0c Watchdog.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Watchdog.cpp	Fri Dec 20 19:42:32 2013 +0000
@@ -0,0 +1,15 @@
+#include "mbed.h"
+#include "Watchdog.h"
+
+void Watchdog::kick(int WDTseconds) {
+    if(WDTseconds < 1) WDTseconds = 1;      //minimum watchdog time is 1 sec
+    if(WDTseconds > 134) WDTseconds = 134;  //maximum watchdog time is 134 sec
+    LPC_WDT->TC = 125000 * WDTseconds;      //125000 * 8uS = 1.0 second tics
+    LPC_WDT->MOD = 0x3;                     //enable and restart watchdog
+    Watchdog::kick();
+}
+
+void Watchdog::kick() {
+    LPC_WDT->FEED = 0xaa;                   //kick sequence into FEED register
+    LPC_WDT->FEED = 0x55;
+}

diff -r 000000000000 -r fc62d045ca0c Watchdog.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Watchdog.h	Fri Dec 20 19:42:32 2013 +0000
@@ -0,0 +1,57 @@
+#ifndef WATCHDOG_4088_H
+#define WATCHDOG_4088_H
+
+#include "mbed.h"
+
+/** Routines to set and kick the Watchdog timer for the LPC4088.
+ *
+ *   The LPC4088 has a fixed, internal 500KHz oscillator which
+ *   is divided by 4 to give an 8uS master clock to the Watchdog countdown timer.
+ *
+ *   User inputs a value from 1 to 134 seconds when initializing the Watchdog
+ *   timer. The user's input number is multiplied by 125k and then placed into 
+ *   the countdown timer.
+ *
+ *   The user is responsible for "kicking" the Watchdog before the timeout interval 
+ *   expires, otherwise the LPC4088 will automatically reboot.
+ *
+ * @code
+ * #include "mbed.h"
+ * #include "Watchdog.h" 
+ *
+ * Watchdog wdt;
+ *
+ * int main() {
+ *     initialization code....
+ *     wdt.kick(20);           //init the watchdog for a 20 second timeout
+ *     while(1) {
+ *         wait_ms(1000);      //do some code
+ *         wdt.kick();         //kick the watchdog before 20 seconds is up
+ *     }
+ * }
+ * @endcode
+ *
+ */
+/* Watchdog controller class
+ */
+class Watchdog {
+
+public:
+    /** Create a Watchdog object and initialize timeout in seconds
+     *
+     * @param int timeout in seconds. Range (1 - 134)
+     */
+    void kick(int WDTseconds);
+    
+    
+    /** Keep alive by kicking the Watchdog occasionally
+     *
+     * @param NONE
+     */
+    void kick();
+
+private:
+    int WDTseconds;
+};
+
+#endif