circuitpython/stmhal/wdt.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 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.
*/
#include <stdio.h>
#include "py/runtime.h"
#include "wdt.h"
typedef struct _pyb_wdt_obj_t {
mp_obj_base_t base;
} pyb_wdt_obj_t;
STATIC pyb_wdt_obj_t pyb_wdt = {{&pyb_wdt_type}};
STATIC mp_obj_t pyb_wdt_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
// parse arguments
enum { ARG_id, ARG_timeout };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_id, MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_timeout, MP_ARG_INT, {.u_int = 5000} },
};
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
mp_int_t id = args[ARG_id].u_int;
if (id != 0) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "WDT(%d) doesn't exist", id));
}
// timeout is in milliseconds
mp_int_t timeout = args[ARG_timeout].u_int;
// compute prescaler
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("WDT timeout too short");
} else if (timeout > 0xfff) {
mp_raise_ValueError("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 (mp_obj_t)&pyb_wdt;
}
STATIC mp_obj_t pyb_wdt_feed(mp_obj_t self_in) {
(void)self_in;
IWDG->KR = 0xaaaa;
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(pyb_wdt_feed_obj, pyb_wdt_feed);
STATIC const mp_rom_map_elem_t pyb_wdt_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_feed), MP_ROM_PTR(&pyb_wdt_feed_obj) },
};
STATIC MP_DEFINE_CONST_DICT(pyb_wdt_locals_dict, pyb_wdt_locals_dict_table);
const mp_obj_type_t pyb_wdt_type = {
{ &mp_type_type },
.name = MP_QSTR_WDT,
.make_new = pyb_wdt_make_new,
.locals_dict = (mp_obj_dict_t*)&pyb_wdt_locals_dict,
};