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