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Diffstat (limited to 'libmaple/include/libmaple/iwdg.h')
| -rw-r--r-- | libmaple/include/libmaple/iwdg.h | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/libmaple/include/libmaple/iwdg.h b/libmaple/include/libmaple/iwdg.h new file mode 100644 index 0000000..3a16c55 --- /dev/null +++ b/libmaple/include/libmaple/iwdg.h @@ -0,0 +1,115 @@ +/****************************************************************************** + * 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 libmaple/include/libmaple/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 _LIBMAPLE_IWDG_H_ +#define _LIBMAPLE_IWDG_H_ + +#ifdef __cplusplus +extern "C"{ +#endif + +#include <libmaple/libmaple_types.h> + +/* + * 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 (1U << IWDG_SR_RVU_BIT) +#define IWDG_SR_PVU (1U << 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 |