IWDG

This module contains low level functions for watchdog configuration. More...

Files
file	stm32f103cb_iwdg.h
	Header file for stm32f103cb independant watchdog timer.

Functions
mcu_error	IWDG_setup (uint32_t timeout)
	Initialize the independant watchdog timer. More...
bool	IWDG_resetCheck (void)
	Check if reset occured from watchdog timeout. More...
void	IWDG_feed (void)
	Reload the watchdog timer. More...

Detailed Description

This module contains low level functions for watchdog configuration.

The stm32f103cb independant watchdog timer can be configured with a timeout of up to 26 seconds. To avoid a forced reset the timer should be reloaded with IWDG_feed() before the timeout time has elapsed.

IWDG_resetCheck() can be used to check if a reset has occured from a watchdog timeout.

Author

Stuart Ianna

Version

0.1

Date

June 2018

Copyright

GNU GPLv3

Warning

None

Bug:

None

Todo:

Verified Compilers

• arm-none-eabi-gcc (15:4.9.3+svn231177-1) 4.9.3 20150529 (prerelease)

Working example

This program's loop time increasing by a factor of 10 each itteration. The increasing time causes a forced reset by the watchdog timer.

#include <stm32f103cb_core.h>
#include <coms128.h>

volatile int cap = 10;
int count;

int main(void){

    //Serial setup
    USART_setup(USART_1);
    USART_setBaud(USART_1,USART_BAUD_115200);
    COMS(USART_1);

    if(IWDG_resetCheck()){

        //Ideally this should be first part of program.
        //Located here to demonstrate example with terminal
        printl("Reset from IWDG");
        
    }
    else{

        printl("Normal reset");
    }

    //Setup watchdog for reset after 1 second if not fed.
    IWDG_setup(1000);

    while (1){

        //Feed the dog
        prints("Feeding no");
        printl(count++);
        IWDG_feed();
        for(volatile int i = 0; i < cap; i++);

        //Each time the loop gets longer
        cap *= 10;
    }

    return 0;
}

Function Documentation

void IWDG_feed

(

void

)

Reload the watchdog timer.

This should be called at least as often as the watchdog timeout value to avoid forced reset.

Definition at line 110 of file stm32f103cb_iwdg.c.

bool IWDG_resetCheck

(

void

)

Check if reset occured from watchdog timeout.

Returns

• 1 if reset occured from watchdog
• 0 from other reset type.

Definition at line 98 of file stm32f103cb_iwdg.c.

mcu_error IWDG_setup

(

uint32_t

timeout

)

Initialize the independant watchdog timer.

This must be called before any other feature is used.

Parameters

timeout

The timeout period in milliseconds

Returns

Error number as defined in mcu_error, E_IWDG_NOERROR if no error, E_IWDG_PERIOD if period is too long.

Definition at line 19 of file stm32f103cb_iwdg.c.