reflow-oven-control-sw/stm-firmware/include/reflow-controller/safety/watchdog.h

/* Reflow Oven Controller
*
* Copyright (C) 2020  Mario Hüttel <mario.huettel@gmx.net>
*
* This file is part of the Reflow Oven Controller Project.
*
* The reflow oven controller is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* The Reflow Oven Control Firmware is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the reflow oven controller project.
* If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef __WATCHDOG_H__
#define __WATCHDOG_H__

#include <reflow-controller/safety/safety-config.h>
#include <stdint.h>
#include <stdbool.h>

/**
 * @brief Setup the watchdog for the safety controller
 *
 * The watchdog timeout can be calculated with:
 * \f[ t = \frac{(\mathrm{RELOAD_VAL} + 1)\cdot \mathrm{PRESCALER}}{32000 } s\f]
 *
 * Valid prescaler values are: 4, 8, 16, 32, 64, 128, 256.
 * @param prescaler Prescaler to use for the 32 KHz LSI clock
 * @param reload_value Reload value to reload the timer with when reset. 0 to 0xFFF
 * @return 0 if successful
 * @return -1 if prescaler is wrong
 * @return -2 if a reload value > 0xFFF is selected. 0xFFF will be used in this case
 * @note Once the watchdog is enabled, it cannot be turned off!
 */
int watchdog_setup(uint16_t prescaler, uint16_t reload_value);

/**
 * @brief Reset watchdog counter
 * @param magic Magic value to prevent this fuinction from being called randomly
 * @return 0 if successful
 */
int watchdog_ack(uint32_t magic);

#endif /* __WATCHDOG_H__ */