components/esp32-owb/include/owb.h

changeset 0
b74b0e4902c3
child 29
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/components/esp32-owb/include/owb.h	Sat Oct 20 13:23:15 2018 +0200
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+/*
+ * 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
+ * @brief Interface definitions for the 1-Wire bus component.
+ *
+ * This component provides structures and functions that are useful for communicating
+ * with devices connected to a Maxim Integrated 1-Wire® bus via a single GPIO.
+ *
+ * Currently only externally powered devices are supported. Parasitic power is not supported.
+ */
+
+#ifndef ONE_WIRE_BUS_H
+#define ONE_WIRE_BUS_H
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+// ROM commands
+#define OWB_ROM_SEARCH        0xF0
+#define OWB_ROM_READ          0x33
+#define OWB_ROM_MATCH         0x55
+#define OWB_ROM_SKIP          0xCC
+#define OWB_ROM_SEARCH_ALARM  0xEC
+
+#define OWB_ROM_CODE_STRING_LENGTH (17)  ///< Typical length of OneWire bus ROM ID as ASCII hex string, including null terminator
+
+struct owb_driver;
+
+/**
+ * @brief Structure containing 1-Wire bus information relevant to a single instance.
+ */
+typedef struct
+{
+    const struct _OneWireBus_Timing * timing;   ///< Pointer to timing information
+    bool use_crc;                               ///< True if CRC checks are to be used when retrieving information from a device on the bus
+
+    const struct owb_driver *driver;
+} OneWireBus;
+
+/**
+ * @brief Represents a 1-Wire ROM Code. This is a sequence of eight bytes, where
+ *        the first byte is the family number, then the following 6 bytes form the
+ *        serial number. The final byte is the CRC8 check byte.
+ */
+typedef union
+{
+    /// Provides access via field names
+    struct fields
+    {
+        uint8_t family[1];         ///< family identifier (1 byte, LSB - read/write first)
+        uint8_t serial_number[6];  ///< serial number (6 bytes)
+        uint8_t crc[1];            ///< CRC check byte (1 byte, MSB - read/write last)
+    } fields;                      ///< Provides access via field names
+
+    uint8_t bytes[8];              ///< Provides raw byte access
+
+} OneWireBus_ROMCode;
+
+/**
+ * @brief Represents the state of a device search on the 1-Wire bus.
+ *
+ *        Pass a pointer to this structure to owb_search_first() and
+ *        owb_search_next() to iterate through detected devices on the bus.
+ */
+typedef struct
+{
+    OneWireBus_ROMCode rom_code;
+    int last_discrepancy;
+    int last_family_discrepancy;
+    int last_device_flag;
+} OneWireBus_SearchState;
+
+typedef enum
+{
+    OWB_STATUS_OK,
+    OWB_STATUS_NOT_INITIALIZED,
+    OWB_STATUS_PARAMETER_NULL,
+    OWB_STATUS_DEVICE_NOT_RESPONDING,
+    OWB_STATUS_CRC_FAILED,
+    OWB_STATUS_TOO_MANY_BITS,
+    OWB_STATUS_HW_ERROR
+} owb_status;
+
+/** NOTE: Driver assumes that (*init) was called prior to any other methods */
+struct owb_driver
+{
+    const char* name;
+
+    owb_status (*uninitialize)(const OneWireBus * bus);
+
+    owb_status (*reset)(const OneWireBus * bus, bool *is_present);
+
+    /** NOTE: The data is shifted out of the low bits, eg. it is written in the order of lsb to msb */
+    owb_status (*write_bits)(const OneWireBus *bus, uint8_t out, int number_of_bits_to_write);
+
+    /** NOTE: Data is read into the high bits, eg. each bit read is shifted down before the next bit is read */
+    owb_status (*read_bits)(const OneWireBus *bus, uint8_t *in, int number_of_bits_to_read);
+};
+
+#define container_of(ptr, type, member) ({                      \
+        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
+        (type *)( (char *)__mptr - offsetof(type,member) );})
+
+/**
+ * @brief call to release resources after completing use of the OneWireBus
+ */
+owb_status owb_uninitialize(OneWireBus * bus);
+
+/**
+ * @brief Enable or disable use of CRC checks on device communications.
+ * @param[in] bus Pointer to initialised bus instance.
+ * @param[in] use_crc True to enable CRC checks, false to disable.
+ * @return status
+ */
+owb_status owb_use_crc(OneWireBus * bus, bool use_crc);
+
+/**
+ * @brief Read ROM code from device - only works when there is a single device on the bus.
+ * @param[in] bus Pointer to initialised bus instance.
+ * @param[out] rom_code the value read from the device's rom
+ * @return status
+ */
+owb_status owb_read_rom(const OneWireBus * bus, OneWireBus_ROMCode *rom_code);
+
+/**
+ * @brief Verify the device specified by ROM code is present.
+ * @param[in] bus Pointer to initialised bus instance.
+ * @param[in] rom_code ROM code to verify.
+ * @param[out] is_present set to true if a device is present, false if not
+ * @return status
+ */
+owb_status owb_verify_rom(const OneWireBus * bus, OneWireBus_ROMCode rom_code, bool* is_present);
+
+/**
+ * @brief Reset the 1-Wire bus.
+ * @param[in] bus Pointer to initialised bus instance.
+ * @param[out] is_present set to true if at least one device is present on the bus
+ * @return status
+ */
+owb_status owb_reset(const OneWireBus * bus, bool* a_device_present);
+
+/**
+ * @brief Write a single byte to the 1-Wire bus.
+ * @param[in] bus Pointer to initialised bus instance.
+ * @param[in] data Byte value to write to bus.
+ * @return status
+ */
+owb_status owb_write_byte(const OneWireBus * bus, uint8_t data);
+
+/**
+ * @brief Read a single byte from the 1-Wire bus.
+ * @param[in] bus Pointer to initialised bus instance.
+ * @param[out] out The byte value read from the bus.
+ * @return status
+ */
+owb_status owb_read_byte(const OneWireBus * bus, uint8_t *out);
+
+/**
+ * @brief Read a number of bytes from the 1-Wire bus.
+ * @param[in] bus Pointer to initialised bus instance.
+ * @param[in, out] buffer Pointer to buffer to receive read data.
+ * @param[in] len Number of bytes to read, must not exceed length of receive buffer.
+ * @return status.
+ */
+owb_status owb_read_bytes(const OneWireBus * bus, uint8_t * buffer, size_t len);
+
+/**
+ * @brief Write a number of bytes to the 1-Wire bus.
+ * @param[in] bus Pointer to initialised bus instance.
+ * @param[in] buffer Pointer to buffer to write data from.
+ * @param[in] len Number of bytes to write.
+ * @return status
+ */
+owb_status owb_write_bytes(const OneWireBus * bus, const uint8_t * buffer, size_t len);
+
+/**
+ * @brief Write a ROM code to the 1-Wire bus ensuring LSB is sent first.
+ * @param[in] bus Pointer to initialised bus instance.
+ * @param[in] rom_code ROM code to write to bus.
+ * @return status
+ */
+owb_status owb_write_rom_code(const OneWireBus * bus, OneWireBus_ROMCode rom_code);
+
+/**
+ * @brief 1-Wire 8-bit CRC lookup.
+ * @param[in] crc Starting CRC value. Pass in prior CRC to accumulate.
+ * @param[in] data Byte to feed into CRC.
+ * @return Resultant CRC value.
+ *         Should be zero if last byte was the CRC byte and the CRC matches.
+ */
+uint8_t owb_crc8_byte(uint8_t crc, uint8_t data);
+
+/**
+ * @brief 1-Wire 8-bit CRC lookup with accumulation over a block of bytes.
+ * @param[in] crc Starting CRC value. Pass in prior CRC to accumulate.
+ * @param[in] data Array of bytes to feed into CRC.
+ * @param[in] len Length of data array in bytes.
+ * @return Resultant CRC value.
+ *         Should be zero if last byte was the CRC byte and the CRC matches.
+ */
+uint8_t owb_crc8_bytes(uint8_t crc, const uint8_t * data, size_t len);
+
+/**
+ * @brief Locates the first device on the 1-Wire bus, if present.
+ * @param[in] bus Pointer to initialised bus instance.
+ * @param[in,out] state Pointer to an existing search state structure.
+ * @param[out] found_device True if a device is found, false if no devices are found.
+ *         If a device is found, the ROM Code can be obtained from the state.
+ * @return status
+ */
+owb_status owb_search_first(const OneWireBus * bus, OneWireBus_SearchState * state, bool *found_device);
+
+/**
+ * @brief Locates the next device on the 1-Wire bus, if present, starting from
+ *        the provided state. Further calls will yield additional devices, if present.
+ * @param[in] bus Pointer to initialised bus instance.
+ * @param[in,out] state Pointer to an existing search state structure.
+ * @param[out] found_device True if a device is found, false if no devices are found.
+ *         If a device is found, the ROM Code can be obtained from the state.
+ * @return status
+ */
+owb_status owb_search_next(const OneWireBus * bus, OneWireBus_SearchState * state, bool *found_device);
+
+/**
+ * @brief Create a string representation of a ROM code, most significant byte (CRC8) first.
+ * @param[in] rom_code The ROM code to convert to string representation.
+ * @param[out] buffer The destination for the string representation. It will be null terminated.
+ * @param[in] len The length of the buffer in bytes. 64-bit ROM codes require 16 characters
+ *                to represent as a string, plus a null terminator, for 17 bytes.
+ *                See OWB_ROM_CODE_STRING_LENGTH.
+ * @return pointer to the byte beyond the last byte written
+ */
+char * owb_string_from_rom_code(OneWireBus_ROMCode rom_code, char * buffer, size_t len);
+
+#include "owb_gpio.h"
+#include "owb_rmt.h"
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // ONE_WIRE_BUS_H

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