/* * This file is part of the Micro Python project, http://micropython.org/ * * The MIT License (MIT) * * Copyright (c) 2017 Scott Shawcroft for Adafruit Industries * * 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 "common-hal/microcontroller/types.h" #include "shared-bindings/bitbangio/OneWire.h" #include "shared-bindings/microcontroller/__init__.h" #include "shared-bindings/digitalio/DigitalInOut.h" #include "shared-module/bitbangio/types.h" // Durations are taken from here: https://www.maximintegrated.com/en/app-notes/index.mvp/id/126 void shared_module_bitbangio_onewire_construct(bitbangio_onewire_obj_t* self, const mcu_pin_obj_t* pin) { self->pin.base.type = &digitalio_digitalinout_type; common_hal_digitalio_digitalinout_construct(&self->pin, pin); } void shared_module_bitbangio_onewire_deinit(bitbangio_onewire_obj_t* self) { common_hal_digitalio_digitalinout_deinit(&self->pin); } bool shared_module_bitbangio_onewire_reset(bitbangio_onewire_obj_t* self) { common_hal_mcu_disable_interrupts(); common_hal_digitalio_digitalinout_switch_to_output(&self->pin, false, DRIVE_MODE_OPEN_DRAIN); common_hal_mcu_delay_us(480); common_hal_digitalio_digitalinout_switch_to_input(&self->pin, PULL_NONE); common_hal_mcu_delay_us(70); bool value = common_hal_digitalio_digitalinout_get_value(&self->pin); common_hal_mcu_delay_us(410); common_hal_mcu_enable_interrupts(); return value; } bool shared_module_bitbangio_onewire_read_bit(bitbangio_onewire_obj_t* self) { common_hal_mcu_disable_interrupts(); common_hal_digitalio_digitalinout_switch_to_output(&self->pin, false, DRIVE_MODE_OPEN_DRAIN); common_hal_mcu_delay_us(6); common_hal_digitalio_digitalinout_switch_to_input(&self->pin, PULL_NONE); // TODO(tannewt): Test with more devices and maybe make the delays // configurable. This should be 9 by the datasheet but all bits read as 1 // then. common_hal_mcu_delay_us(6); bool value = common_hal_digitalio_digitalinout_get_value(&self->pin); common_hal_mcu_delay_us(55); common_hal_mcu_enable_interrupts(); return value; } void shared_module_bitbangio_onewire_write_bit(bitbangio_onewire_obj_t* self, bool bit) { common_hal_mcu_disable_interrupts(); common_hal_digitalio_digitalinout_switch_to_output(&self->pin, false, DRIVE_MODE_OPEN_DRAIN); common_hal_mcu_delay_us(bit? 6 : 60); common_hal_digitalio_digitalinout_switch_to_input(&self->pin, PULL_NONE); common_hal_mcu_delay_us(bit? 64 : 10); common_hal_mcu_enable_interrupts(); }