Watchdog timer for KL26

mridulpandey — Wed, 12 Aug 2015 14:08:02 GMT

Hi,

I was trying to find something in the documents provided by freescale and also sample BSP provided by freescale. I wanted to use watchdog timer for my project. Can someone please help me with a sample code of watchdog timer initialisation, setting the timer and using it.

Please post me some example to learn watchdog functioning on freedom kl26 board.

Thanks.

Re: Watchdog timer for KL26

Jorge_Gonzalez — Mon, 02 Nov 2020 13:20:48 GMT

Hello Mridul Pandey:

The watchdog or COP (Computer Operating Properly) in KL26 is very simple and not hard to configure. You only need to configure the SIM_COPC register according to Table 3-23 COP configuration options in the KL26 Reference Manual:

In the example code below for FRDM-KL26 the COP is configured for a 1 second timeout. If you compile with the macro RESET_WDOG = 0 the blue LED will toggle each second because the MCU is resetting. Otherwise if you compile with RESET_WDOG = 1, the counter is refreshed in the while loop and the MCU does not reset.

:smileyalert: Make sure that the SIM_COPC is not written in the startup code of the project. Typically the watchdog is disabled at startup and this register can only be written once after reset.

#include "MKL26Z4.h"
#define RESET_WDOG    0
int counter = 0;
int main(void)
{
    /* Initialize blue LED */
    SIM_SCGC5 |= SIM_SCGC5_PORTD_MASK;    // Enable clock gate for PORTD
    PORTD_PCR5 = PORT_PCR_MUX(1);        // PTD5 as GPIO
    GPIOD_PDDR |= (1 << 5);                // PTD5 as output
    GPIOD_PDOR &= !(1 << 5);        // Output 0 [Blue LED off]
    for (counter = 0; counter <= 50000; counter++){}    // Delay
    GPIOD_PDOR |= (1 << 5);            // Output 1 [Blue LED on
    /* Configure watchdog (COP) */
    SIM_COPC = 0xC; // COPT = 11    [Timeout after 2^10 LPO cycles] OR [Timeout after 2^18 bus clock cycles]
                    // COPCLKS = 0    [LPO (1kHz) clock selected]
                    // COPW = 0        [Normal mode]
                    // Timeout = (1/LPO clock) x 2^10 = (1/1 kHz) x 2^18 = 1 s
    while(1)
    {
#if RESET_WDOG
        for (counter = 0; counter <= 50000; counter++){}    // Delay
        SIM_SRVCOP = 0x55;
        SIM_SRVCOP = 0xAA;
#endif
    }
    return 0;
}

The COP is also supported by the KSDK platform library, which you can download from the platform page: Software Development Kit for Kinetis MCUs|Freescale

Once installed you can find an example for COP in the next installation path:

C:\Freescale\KSDK_1.2.0\examples\frdmkl26z\driver_examples\cop

Regards!,
Jorge Gonzalez

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Re: Watchdog timer for KL26

mridulpandey — Wed, 19 Aug 2015 12:13:09 GMT

Thanks Jorge,

It was a great help. I Tried it and it worked fine. :smileyhappy:

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