micropython/ports/stm32/machine_wdt.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016-2023 Damien P. George
*
* 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.
*/
// This file is never compiled standalone, it's included directly from
// extmod/machine_wdt.c via MICROPY_PY_MACHINE_WDT_INCLUDEFILE.
#include "py/mphal.h"
#if defined(STM32H7)
#define IWDG (IWDG1)
#endif
typedef struct _machine_wdt_obj_t {
mp_obj_base_t base;
} machine_wdt_obj_t;
STATIC const machine_wdt_obj_t machine_wdt = {{&machine_wdt_type}};
STATIC machine_wdt_obj_t *mp_machine_wdt_make_new_instance(mp_int_t id, mp_int_t timeout_ms) {
if (id != 0) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("WDT(%d) doesn't exist"), id);
}
// compute prescaler
int32_t timeout = timeout_ms;
uint32_t prescaler;
for (prescaler = 0; prescaler < 6 && timeout >= 512; ++prescaler, timeout /= 2) {
}
// convert milliseconds to ticks
timeout *= 8; // 32kHz / 4 = 8 ticks per millisecond (approx)
if (timeout <= 0) {
mp_raise_ValueError(MP_ERROR_TEXT("WDT timeout too short"));
} else if (timeout > 0xfff) {
mp_raise_ValueError(MP_ERROR_TEXT("WDT timeout too long"));
}
timeout -= 1;
// set the reload register
while (IWDG->SR & 2) {
}
IWDG->KR = 0x5555;
IWDG->RLR = timeout;
// set the prescaler
while (IWDG->SR & 1) {
}
IWDG->KR = 0x5555;
IWDG->PR = prescaler;
// start the watch dog
IWDG->KR = 0xcccc;
return (machine_wdt_obj_t *)&machine_wdt;
}
STATIC void mp_machine_wdt_feed(machine_wdt_obj_t *self) {
(void)self;
IWDG->KR = 0xaaaa;
}