163 lines
5.7 KiB
C
163 lines
5.7 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2015-2017 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include "py/obj.h"
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#include "py/mphal.h"
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/******************************************************************************/
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// Low-level 1-Wire routines
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#define TIMING_RESET1 (480)
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#define TIMING_RESET2 (70)
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#define TIMING_RESET3 (410)
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#define TIMING_READ1 (5)
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#define TIMING_READ2 (5)
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#define TIMING_READ3 (40)
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#define TIMING_WRITE1 (10)
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#define TIMING_WRITE2 (50)
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#define TIMING_WRITE3 (10)
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STATIC int onewire_bus_reset(mp_hal_pin_obj_t pin) {
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mp_hal_pin_write(pin, 0);
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mp_hal_delay_us(TIMING_RESET1);
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uint32_t i = mp_hal_quiet_timing_enter();
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mp_hal_pin_write(pin, 1);
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mp_hal_delay_us_fast(TIMING_RESET2);
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int status = !mp_hal_pin_read(pin);
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mp_hal_quiet_timing_exit(i);
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mp_hal_delay_us(TIMING_RESET3);
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return status;
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}
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STATIC int onewire_bus_readbit(mp_hal_pin_obj_t pin) {
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mp_hal_pin_write(pin, 1);
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uint32_t i = mp_hal_quiet_timing_enter();
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mp_hal_pin_write(pin, 0);
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mp_hal_delay_us_fast(TIMING_READ1);
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mp_hal_pin_write(pin, 1);
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mp_hal_delay_us_fast(TIMING_READ2);
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int value = mp_hal_pin_read(pin);
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mp_hal_quiet_timing_exit(i);
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mp_hal_delay_us_fast(TIMING_READ3);
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return value;
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}
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STATIC void onewire_bus_writebit(mp_hal_pin_obj_t pin, int value) {
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uint32_t i = mp_hal_quiet_timing_enter();
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mp_hal_pin_write(pin, 0);
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mp_hal_delay_us_fast(TIMING_WRITE1);
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if (value) {
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mp_hal_pin_write(pin, 1);
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}
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mp_hal_delay_us_fast(TIMING_WRITE2);
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mp_hal_pin_write(pin, 1);
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mp_hal_delay_us_fast(TIMING_WRITE3);
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mp_hal_quiet_timing_exit(i);
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}
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/******************************************************************************/
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// MicroPython bindings
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STATIC mp_obj_t onewire_reset(mp_obj_t pin_in) {
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return mp_obj_new_bool(onewire_bus_reset(mp_hal_get_pin_obj(pin_in)));
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_reset_obj, onewire_reset);
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STATIC mp_obj_t onewire_readbit(mp_obj_t pin_in) {
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return MP_OBJ_NEW_SMALL_INT(onewire_bus_readbit(mp_hal_get_pin_obj(pin_in)));
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_readbit_obj, onewire_readbit);
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STATIC mp_obj_t onewire_readbyte(mp_obj_t pin_in) {
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mp_hal_pin_obj_t pin = mp_hal_get_pin_obj(pin_in);
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uint8_t value = 0;
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for (int i = 0; i < 8; ++i) {
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value |= onewire_bus_readbit(pin) << i;
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}
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return MP_OBJ_NEW_SMALL_INT(value);
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_readbyte_obj, onewire_readbyte);
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STATIC mp_obj_t onewire_writebit(mp_obj_t pin_in, mp_obj_t value_in) {
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onewire_bus_writebit(mp_hal_get_pin_obj(pin_in), mp_obj_get_int(value_in));
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return mp_const_none;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_2(onewire_writebit_obj, onewire_writebit);
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STATIC mp_obj_t onewire_writebyte(mp_obj_t pin_in, mp_obj_t value_in) {
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mp_hal_pin_obj_t pin = mp_hal_get_pin_obj(pin_in);
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int value = mp_obj_get_int(value_in);
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for (int i = 0; i < 8; ++i) {
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onewire_bus_writebit(pin, value & 1);
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value >>= 1;
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}
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return mp_const_none;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_2(onewire_writebyte_obj, onewire_writebyte);
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STATIC mp_obj_t onewire_crc8(mp_obj_t data) {
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mp_buffer_info_t bufinfo;
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mp_get_buffer_raise(data, &bufinfo, MP_BUFFER_READ);
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uint8_t crc = 0;
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for (size_t i = 0; i < bufinfo.len; ++i) {
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uint8_t byte = ((uint8_t*)bufinfo.buf)[i];
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for (int b = 0; b < 8; ++b) {
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uint8_t fb_bit = (crc ^ byte) & 0x01;
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if (fb_bit == 0x01) {
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crc = crc ^ 0x18;
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}
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crc = (crc >> 1) & 0x7f;
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if (fb_bit == 0x01) {
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crc = crc | 0x80;
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}
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byte = byte >> 1;
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}
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}
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return MP_OBJ_NEW_SMALL_INT(crc);
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(onewire_crc8_obj, onewire_crc8);
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STATIC const mp_rom_map_elem_t onewire_module_globals_table[] = {
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{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_onewire) },
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{ MP_ROM_QSTR(MP_QSTR_reset), MP_ROM_PTR(&onewire_reset_obj) },
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{ MP_ROM_QSTR(MP_QSTR_readbit), MP_ROM_PTR(&onewire_readbit_obj) },
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{ MP_ROM_QSTR(MP_QSTR_readbyte), MP_ROM_PTR(&onewire_readbyte_obj) },
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{ MP_ROM_QSTR(MP_QSTR_writebit), MP_ROM_PTR(&onewire_writebit_obj) },
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{ MP_ROM_QSTR(MP_QSTR_writebyte), MP_ROM_PTR(&onewire_writebyte_obj) },
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{ MP_ROM_QSTR(MP_QSTR_crc8), MP_ROM_PTR(&onewire_crc8_obj) },
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};
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STATIC MP_DEFINE_CONST_DICT(onewire_module_globals, onewire_module_globals_table);
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const mp_obj_module_t mp_module_onewire = {
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.base = { &mp_type_module },
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.globals = (mp_obj_dict_t*)&onewire_module_globals,
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};
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