David Smart / Watchdog

This provides a basic Watchdog service, and includes a startup detection to determine if the reset was caused by the WD.

Dependents:   A_CANAdapter LeonardoMbos AVC_2012 RT_CAN ... more

Using this Watchdog Class

#include "Watchdog.h"

Watchdog wd;

...
void main() {
   if (wd.WatchdogCausedReset())
       pc.printf("Watchdog caused reset.\r\n");
      
   wd.Configure(3.0);       // sets the timeout interval
   for (;;) {
        wd.Service();       // kick the dog before the timeout
        // do other work
   }
}

Watchdog.cpp

Committer:
WiredHome
Date:
2011-03-20
Revision:
0:7a316f14da9c
Child:
2:2873f068f325

File content as of revision 0:7a316f14da9c:


#include "mbed.h"
#include "Watchdog.h"



/// Watchdog gets instantiated at the module level
Watchdog::Watchdog() {
    wdreset = (LPC_WDT->WDMOD >> 2) & 1;
}

/// Load timeout value in watchdog timer and enable
void Watchdog::Configure(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
    Service();
}

/// "Service", "kick" or "feed" the dog - reset the watchdog timer
/// by writing this required bit pattern
void Watchdog::Service() {
    LPC_WDT->WDFEED = 0xAA;
    LPC_WDT->WDFEED = 0x55;
}

/// get the flag to indicate if the watchdog causes the reset
bool Watchdog::WatchdogCausedReset() {
    return wdreset;
}