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/******************************************************************************
* The MIT License
*
* Copyright (c) 2010 Michael Hope.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*****************************************************************************/
/**
* @file iwdg.h
* @author Michael Hope, Marti Bolivar <mbolivar@leaflabs.com>
* @brief Independent watchdog support.
*
* To use the independent watchdog, first call iwdg_init() with the
* appropriate prescaler and IWDG counter reload values for your
* application. Afterwards, you must periodically call iwdg_feed()
* before the IWDG counter reaches 0 to reset the counter to its
* reload value. If you do not, the chip will reset.
*
* Once started, the independent watchdog cannot be turned off.
*/
#ifndef _IWDG_H_
#define _IWDG_H_
#include "libmaple_types.h"
#include "util.h"
#ifdef __cplusplus
extern "C"{
#endif
/*
* Register map
*/
/** Independent watchdog register map type. */
typedef struct iwdg_reg_map {
__io uint32 KR; /**< Key register. */
__io uint32 PR; /**< Prescaler register. */
__io uint32 RLR; /**< Reload register. */
__io uint32 SR; /**< Status register */
} iwdg_reg_map;
/** Independent watchdog base pointer */
#define IWDG_BASE ((struct iwdg_reg_map*)0x40003000)
/*
* Register bit definitions
*/
/* Key register */
#define IWDG_KR_UNLOCK 0x5555
#define IWDG_KR_FEED 0xAAAA
#define IWDG_KR_START 0xCCCC
/* Prescaler register */
#define IWDG_PR_DIV_4 0x0
#define IWDG_PR_DIV_8 0x1
#define IWDG_PR_DIV_16 0x2
#define IWDG_PR_DIV_32 0x3
#define IWDG_PR_DIV_64 0x4
#define IWDG_PR_DIV_128 0x5
#define IWDG_PR_DIV_256 0x6
/* Status register */
#define IWDG_SR_RVU_BIT 1
#define IWDG_SR_PVU_BIT 0
#define IWDG_SR_RVU BIT(IWDG_SR_RVU_BIT)
#define IWDG_SR_PVU BIT(IWDG_SR_PVU_BIT)
/**
* @brief Independent watchdog prescalers.
*
* These divide the 40 kHz IWDG clock.
*/
typedef enum iwdg_prescaler {
IWDG_PRE_4 = IWDG_PR_DIV_4, /**< Divide by 4 */
IWDG_PRE_8 = IWDG_PR_DIV_8, /**< Divide by 8 */
IWDG_PRE_16 = IWDG_PR_DIV_16, /**< Divide by 16 */
IWDG_PRE_32 = IWDG_PR_DIV_32, /**< Divide by 32 */
IWDG_PRE_64 = IWDG_PR_DIV_64, /**< Divide by 64 */
IWDG_PRE_128 = IWDG_PR_DIV_128, /**< Divide by 128 */
IWDG_PRE_256 = IWDG_PR_DIV_256 /**< Divide by 256 */
} iwdg_prescaler;
void iwdg_init(iwdg_prescaler prescaler, uint16 reload);
void iwdg_feed(void);
#ifdef __cplusplus
} // extern "C"
#endif
#endif
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