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287 lines
8.3 KiB
287 lines
8.3 KiB
/*
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* MIT License
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*
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* Copyright (c) 2017 David Antliff
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* Copyright (c) 2017 Chris Morgan <chmorgan@gmail.com>
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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 all
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* 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 THE
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* SOFTWARE.
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*/
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/**
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* @file
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*/
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#include <stddef.h>
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#include <stdbool.h>
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#include <inttypes.h>
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#include <string.h>
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#include <stdlib.h>
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#include "freertos/FreeRTOS.h"
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#include "freertos/task.h"
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#include "esp_log.h"
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#include "sdkconfig.h"
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#include "driver/gpio.h"
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#include "owb.h"
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#include "owb_gpio.h"
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static const char * TAG = "owb_gpio";
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// Define PHY_DEBUG to enable GPIO output around when the bus is sampled
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// by the master (this library). This GPIO output makes it possible to
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// validate the master's sampling using an oscilloscope.
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//
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// For the debug GPIO the idle state is low and made high before the 1-wire sample
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// point and low again after the sample point
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#undef PHY_DEBUG
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#ifdef PHY_DEBUG
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// Update these defines to a pin that you can access
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#define PHY_DEBUG_GPIO GPIO_NUM_27
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#define PHY_DEBUG_GPIO_MASK GPIO_SEL_27
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#endif
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/// @cond ignore
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struct _OneWireBus_Timing
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{
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uint32_t A, B, C, D, E, F, G, H, I, J;
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};
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/// @endcond
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// 1-Wire timing delays (standard) in microseconds.
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// Labels and values are from https://www.maximintegrated.com/en/app-notes/index.mvp/id/126
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static const struct _OneWireBus_Timing _StandardTiming = {
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6, // A - read/write "1" master pull DQ low duration
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64, // B - write "0" master pull DQ low duration
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60, // C - write "1" master pull DQ high duration
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10, // D - write "0" master pull DQ high duration
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9, // E - read master pull DQ high duration
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55, // F - complete read timeslot + 10ms recovery
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0, // G - wait before reset
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480, // H - master pull DQ low duration
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70, // I - master pull DQ high duration
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410, // J - complete presence timeslot + recovery
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};
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static void _us_delay(uint32_t time_us)
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{
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ets_delay_us(time_us);
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}
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/// @cond ignore
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#define info_from_bus(owb) container_of(owb, owb_gpio_driver_info, bus)
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/// @endcond
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/**
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* @brief Generate a 1-Wire reset (initialization).
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* @param[in] bus Initialised bus instance.
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* @param[out] is_present true if device is present, otherwise false.
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* @return status
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*/
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static owb_status _reset(const OneWireBus * bus, bool * is_present)
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{
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bool present = false;
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portMUX_TYPE timeCriticalMutex = portMUX_INITIALIZER_UNLOCKED;
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portENTER_CRITICAL(&timeCriticalMutex);
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owb_gpio_driver_info *i = info_from_bus(bus);
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gpio_set_direction(i->gpio, GPIO_MODE_OUTPUT);
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_us_delay(bus->timing->G);
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gpio_set_level(i->gpio, 0); // Drive DQ low
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_us_delay(bus->timing->H);
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gpio_set_direction(i->gpio, GPIO_MODE_INPUT); // Release the bus
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gpio_set_level(i->gpio, 1); // Reset the output level for the next output
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_us_delay(bus->timing->I);
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#ifdef PHY_DEBUG
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gpio_set_level(PHY_DEBUG_GPIO, 1);
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#endif
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int level1 = gpio_get_level(i->gpio);
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#ifdef PHY_DEBUG
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gpio_set_level(PHY_DEBUG_GPIO, 0);
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#endif
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_us_delay(bus->timing->J); // Complete the reset sequence recovery
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#ifdef PHY_DEBUG
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gpio_set_level(PHY_DEBUG_GPIO, 1);
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#endif
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int level2 = gpio_get_level(i->gpio);
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#ifdef PHY_DEBUG
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gpio_set_level(PHY_DEBUG_GPIO, 0);
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#endif
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portEXIT_CRITICAL(&timeCriticalMutex);
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present = (level1 == 0) && (level2 == 1); // Sample for presence pulse from slave
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ESP_LOGD(TAG, "reset: level1 0x%x, level2 0x%x, present %d", level1, level2, present);
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*is_present = present;
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return OWB_STATUS_OK;
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}
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/**
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* @brief Send a 1-Wire write bit, with recovery time.
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* @param[in] bus Initialised bus instance.
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* @param[in] bit The value to send.
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*/
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static void _write_bit(const OneWireBus * bus, int bit)
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{
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int delay1 = bit ? bus->timing->A : bus->timing->C;
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int delay2 = bit ? bus->timing->B : bus->timing->D;
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owb_gpio_driver_info *i = info_from_bus(bus);
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portMUX_TYPE timeCriticalMutex = portMUX_INITIALIZER_UNLOCKED;
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portENTER_CRITICAL(&timeCriticalMutex);
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gpio_set_direction(i->gpio, GPIO_MODE_OUTPUT);
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gpio_set_level(i->gpio, 0); // Drive DQ low
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_us_delay(delay1);
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gpio_set_level(i->gpio, 1); // Release the bus
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_us_delay(delay2);
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portEXIT_CRITICAL(&timeCriticalMutex);
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}
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/**
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* @brief Read a bit from the 1-Wire bus and return the value, with recovery time.
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* @param[in] bus Initialised bus instance.
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*/
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static int _read_bit(const OneWireBus * bus)
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{
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int result = 0;
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owb_gpio_driver_info *i = info_from_bus(bus);
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portMUX_TYPE timeCriticalMutex = portMUX_INITIALIZER_UNLOCKED;
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portENTER_CRITICAL(&timeCriticalMutex);
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gpio_set_direction(i->gpio, GPIO_MODE_OUTPUT);
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gpio_set_level(i->gpio, 0); // Drive DQ low
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_us_delay(bus->timing->A);
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gpio_set_direction(i->gpio, GPIO_MODE_INPUT); // Release the bus
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gpio_set_level(i->gpio, 1); // Reset the output level for the next output
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_us_delay(bus->timing->E);
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#ifdef PHY_DEBUG
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gpio_set_level(PHY_DEBUG_GPIO, 1);
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#endif
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int level = gpio_get_level(i->gpio);
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#ifdef PHY_DEBUG
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gpio_set_level(PHY_DEBUG_GPIO, 0);
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#endif
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_us_delay(bus->timing->F); // Complete the timeslot and 10us recovery
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portEXIT_CRITICAL(&timeCriticalMutex);
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result = level & 0x01;
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return result;
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}
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/**
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* @brief Write 1-Wire data byte.
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* NOTE: The data is shifted out of the low bits, eg. it is written in the order of lsb to msb
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* @param[in] bus Initialised bus instance.
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* @param[in] data Value to write.
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* @param[in] number_of_bits_to_read bits to write
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*/
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static owb_status _write_bits(const OneWireBus * bus, uint8_t data, int number_of_bits_to_write)
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{
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ESP_LOGD(TAG, "write 0x%02x", data);
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for (int i = 0; i < number_of_bits_to_write; ++i)
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{
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_write_bit(bus, data & 0x01);
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data >>= 1;
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}
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return OWB_STATUS_OK;
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}
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/**
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* @brief Read 1-Wire data byte from bus.
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* NOTE: Data is read into the high bits, eg. each bit read is shifted down before the next bit is read
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* @param[in] bus Initialised bus instance.
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* @return Byte value read from bus.
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*/
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static owb_status _read_bits(const OneWireBus * bus, uint8_t *out, int number_of_bits_to_read)
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{
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uint8_t result = 0;
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for (int i = 0; i < number_of_bits_to_read; ++i)
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{
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result >>= 1;
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if (_read_bit(bus))
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{
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result |= 0x80;
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}
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}
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ESP_LOGD(TAG, "read 0x%02x", result);
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*out = result;
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return OWB_STATUS_OK;
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}
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static owb_status _uninitialize(const OneWireBus * bus)
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{
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// Nothing to do here for this driver_info
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return OWB_STATUS_OK;
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}
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static const struct owb_driver gpio_function_table =
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{
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.name = "owb_gpio",
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.uninitialize = _uninitialize,
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.reset = _reset,
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.write_bits = _write_bits,
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.read_bits = _read_bits
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};
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OneWireBus* owb_gpio_initialize(owb_gpio_driver_info * driver_info, int gpio)
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{
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ESP_LOGD(TAG, "%s(): gpio %d\n", __func__, gpio);
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driver_info->gpio = gpio;
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driver_info->bus.driver = &gpio_function_table;
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driver_info->bus.timing = &_StandardTiming;
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driver_info->bus.strong_pullup_gpio = GPIO_NUM_NC;
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// platform specific:
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gpio_pad_select_gpio(driver_info->gpio);
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#ifdef PHY_DEBUG
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gpio_config_t io_conf;
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io_conf.intr_type = GPIO_INTR_DISABLE;
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io_conf.mode = GPIO_MODE_OUTPUT;
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io_conf.pin_bit_mask = PHY_DEBUG_GPIO_MASK;
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io_conf.pull_down_en = GPIO_PULLDOWN_ENABLE;
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io_conf.pull_up_en = GPIO_PULLUP_DISABLE;
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ESP_ERROR_CHECK(gpio_config(&io_conf));
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#endif
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return &(driver_info->bus);
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}
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