ceri clatworthy

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9 years ago.

WatchDog LPC1347

Hello all;

More problems with LPC1347, This time it is the watchdog,

#include "mbed.h"

// data sheet: http://www.nxp.com/documents/user_manual/UM10524.pdf
 
//DigitalOut myled1 (P1_2);
//DigitalOut myled2 (P1_5);
DigitalOut myled3 (P1_28);
DigitalOut myled4 (P0_7);
 
class Watchdog {
public:
    void kick(float s) 
    {
        // 3.5.8 Watchdog oscillator control register
        LPC_SYSCON->WDTOSCCTRL = 0x0021;    //
            //   0x0024;// 0.6 mhz/4 ??  
            //   0x003f; // 0.6 Mhz / 64 -> ?? 0.106667 mS
        
        // 15.8.5 Watchdog Clock Select register
        LPC_WWDT->CLKSEL = 0x01;                // Set CLK src to Watcdog osc                                                                       
        
        //uint32_t clk = SystemCoreClock / 16;    // WD has a fixed /4 prescaler, PCLK default is /4 
        //LPC_WDT->WDTC = s * (float)clk;         
        
        LPC_WWDT->TC = 9375; // ?? 1 second
        LPC_WWDT->MOD = 0x3;                   // Enabled and Reset        

        LPC_WWDT->FEED = 0xAA;
        LPC_WWDT->FEED = 0x55;        
    }
    
    void feed() {
       // LPC_WWDT->FEED = 0xAA;
       // LPC_WWDT->FEED = 0x55;
    }
};
 
Watchdog w;
 
int main() 
{
    printf("Hello World!\r\n");
    w.kick(2.5);
 
    int hang = 0;
    int ReadCountDown;
    while(1) 
    {
        //printf("loop...%d\r\n",hang);
        
        float h = hang / 10.0;
        
        
        ReadCountDown = LPC_WWDT->TV;
        
        // printf("ok T:%4.3f %d\r\n",h,ReadCountDown);  // logging program
        printf("%d %d\r\n",hang, ReadCountDown);
        wait(0.1);
        
        myled3 = !myled3;
        
        if (hang == 30) 
        {
           // w.feed();
            LPC_WWDT->FEED = 0xAA;
            LPC_WWDT->FEED = 0x33;       // force reset by wrong food !!   
            printf ("\r\n Cat Food !!\r\n");   
        }
        else
        {
            myled4 = !myled3;
        }
        
        if (hang > 150) hang = 10;
        hang++;
    }
}

I copied the example from Simon's Watchdog code from - http://mbed.org/forum/mbed/topic/508/

Changed some of the defines to match (compile) those in LPC13Uxx.h

but It does not work,

If I read the TC value, which should be decremented, it is fixed at 255 (default)

if I feed WatchDog with Cat food, no RESET is generated :(

As you can see, in the code, I NEVER feed the dog !!!

Still no reset ??

I know I must be doing some thing wrong, but what ??

Pleas any one ??

Ceri

1 Answer

Erik -
9 years ago.

Try adding at the start:

LPC_SYSCON->SYSAHBCLKCTRL |= 0x8000;

That enables clock for the registers of the watchdog.

In general example code for LPC11u24 WDT for a different purpose (waking from deepsleep): https://developer.mbed.org/users/Sissors/code/WakeUp/file/f3adba7cf7c4/Device/WakeUp_LPC11u24.cpp

Thanks,

it does appear to work now with IRC clock,

#include "mbed.h"

// data sheet: http://www.nxp.com/documents/user_manual/UM10524.pdf
 
//DigitalOut myled1 (P1_2);
//DigitalOut myled2 (P1_5);
DigitalOut myled3 (P1_28);
DigitalOut myled4 (P0_7);

Timer t;
 
class Watchdog {
public:
    void kick(float s) 
    {
        // Table 268. Register overview: Watchdog timer (base address 0x4000 4000)
        
        
        // 3.5.14 System clock control register (SYSAHBCLKCTRL)
        LPC_SYSCON->SYSAHBCLKCTRL |= 0x8000;


        // 3.5.8 Watchdog oscillator control register
        LPC_SYSCON->WDTOSCCTRL = 0x0021;    //
            //   0x0024;// 0.6 mhz/4 ??  
            //   0x003f; // 0.6 Mhz / 64 -> ?? 0.106667 mS
        
        // 15.8.5 Watchdog Clock Select register
        LPC_WWDT->CLKSEL = 0x00;                // Set CLK src to 12MHZ  - Watcdog osc                                                                       
        
        //uint32_t clk = SystemCoreClock / 16;    // WD has a fixed /4 prescaler, PCLK default is /4 
        //LPC_WDT->WDTC = s * (float)clk;         
        
        LPC_WWDT->TC = 3000000;   // 9375; // ?? 1 second
        LPC_WWDT->MOD = 0x3;                   // Enabled and Reset        

        LPC_WWDT->FEED = 0xAA;
        LPC_WWDT->FEED = 0x55;        
    }
    
    void feed() {
       // LPC_WWDT->FEED = 0xAA;
       // LPC_WWDT->FEED = 0x55;
    }
};
 
Watchdog w;
 
int main() 
{
    t.reset();
    t.start();
    
    printf("\r\n\r\nHello World!\r\n");
    w.kick(2.5);
 
    int hang = 0;
    int ReadCountDown;
    while(1) 
    {
        //printf("loop...%d\r\n",hang);
        
        float h = hang / 10.0;
        
        
        ReadCountDown = LPC_WWDT->TV;
        
        // printf("ok T:%4.3f %d\r\n",h,ReadCountDown);  // logging program
        printf("%d %08x,  %d mS .. \r\n",hang, ReadCountDown,  t.read_ms());
        wait(0.01);
        
        myled3 = !myled3;
        
        if (hang == 30) 
        {
           // w.feed();
//            LPC_WWDT->FEED = 0xAA;
//            LPC_WWDT->FEED = 0x33;       // force reset by wrong food !!   
//            printf ("\r\n Cat Food !!\r\n");   
        }
        else
        {
            myled4 = !myled3;
        }
        
        if (hang > 150) hang = 10;
        hang++;
    }
}

this gives 990mS count @ 9600 Baud,

will try to get my oscilloscope on it later, and tweak to get a value - or possibly set to a time out !!!

Would also like to get watchdog timer to work, but this makes me happy :)

Cheers

Ceri

posted by ceri clatworthy 21 Apr 2015