273 lines
9.8 KiB
C
273 lines
9.8 KiB
C
/*
|
|
* 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
|