1-Wire network layer

1-Wire network layer More...

Data Structures
struct	w1_rom
	w1_rom struct. More...
struct	w1_slave_config
	Node specific 1-wire configuration struct. More...

Macros
#define	W1_SEARCH_ALL_FAMILIES   0x00
	This flag can be passed to searches in order to not filter on family ID.
#define	W1_ROM_INIT_ZERO
	Initialize all w1_rom struct members to zero.

Typedefs
typedef void(*	w1_search_callback_t) (struct w1_rom rom, void *user_data)
	Define the application callback handler function signature for searches.

Functions
int	w1_read_rom (const struct device *dev, struct w1_rom *rom)
	Read Peripheral 64-bit ROM.
int	w1_match_rom (const struct device *dev, const struct w1_slave_config *config)
	Select a specific slave by broadcasting a selected ROM.
int	w1_resume_command (const struct device *dev)
	Select the slave last addressed with a Match ROM or Search ROM command.
int	w1_skip_rom (const struct device *dev, const struct w1_slave_config *config)
	Select all slaves regardless of ROM.
int	w1_reset_select (const struct device *dev, const struct w1_slave_config *config)
	In single drop configurations use Skip Select command, otherwise use Match ROM command.
int	w1_write_read (const struct device *dev, const struct w1_slave_config *config, const uint8_t *write_buf, size_t write_len, uint8_t *read_buf, size_t read_len)
	Write then read data from the 1-Wire slave with matching ROM.
int	w1_search_bus (const struct device *dev, uint8_t command, uint8_t family, w1_search_callback_t callback, void *user_data)
	Search 1-wire slaves on the bus.
static int	w1_search_rom (const struct device *dev, w1_search_callback_t callback, void *user_data)
	Search for 1-Wire slave on bus.
static int	w1_search_alarm (const struct device *dev, w1_search_callback_t callback, void *user_data)
	Search for 1-Wire slaves with an active alarm.
static uint64_t	w1_rom_to_uint64 (const struct w1_rom *rom)
	Function to convert a w1_rom struct to an uint64_t.
static void	w1_uint64_to_rom (const uint64_t rom64, struct w1_rom *rom)
	Function to write an uint64_t to struct w1_rom pointer.
static uint8_t	w1_crc8 (const uint8_t *src, size_t len)
	Compute CRC-8 chacksum as defined in the 1-Wire specification.
static uint16_t	w1_crc16 (const uint16_t seed, const uint8_t *src, const size_t len)
	Compute 1-Wire variant of CRC 16.

1-Wire ROM Commands
#define	W1_CMD_SKIP_ROM   0xCC
	This command allows the bus master to read the slave devices without providing their ROM code.
#define	W1_CMD_MATCH_ROM   0x55
	This command allows the bus master to address a specific slave device by providing its ROM code.
#define	W1_CMD_RESUME   0xA5
	This command allows the bus master to resume a previous read out from where it left off.
#define	W1_CMD_READ_ROM   0x33
	This command allows the bus master to read the ROM code from a single slave device.
#define	W1_CMD_SEARCH_ROM   0xF0
	This command allows the bus master to discover the addresses (i.e., ROM codes) of all slave devices on the bus.
#define	W1_CMD_SEARCH_ALARM   0xEC
	This command allows the bus master to identify which devices have experienced an alarm condition.
#define	W1_CMD_OVERDRIVE_SKIP_ROM   0x3C
	This command allows the bus master to address all devices on the bus and then switch them to overdrive speed.
#define	W1_CMD_OVERDRIVE_MATCH_ROM   0x69
	This command allows the bus master to address a specific device and switch it to overdrive speed.

CRC Defines
#define	W1_CRC8_SEED   0x00
	Seed value used to calculate the 1-Wire 8-bit crc.
#define	W1_CRC8_POLYNOMIAL   0x8C
	Polynomial used to calculate the 1-Wire 8-bit crc.
#define	W1_CRC16_SEED   0x0000
	Seed value used to calculate the 1-Wire 16-bit crc.
#define	W1_CRC16_POLYNOMIAL   0xa001
	Polynomial used to calculate the 1-Wire 16-bit crc.

Detailed Description

1-Wire network layer

Macro Definition Documentation

W1_CMD_MATCH_ROM

#define W1_CMD_MATCH_ROM   0x55

#include <zephyr/drivers/w1.h>

This command allows the bus master to address a specific slave device by providing its ROM code.

W1_CMD_OVERDRIVE_MATCH_ROM

#define W1_CMD_OVERDRIVE_MATCH_ROM   0x69

#include <zephyr/drivers/w1.h>

This command allows the bus master to address a specific device and switch it to overdrive speed.

W1_CMD_OVERDRIVE_SKIP_ROM

#define W1_CMD_OVERDRIVE_SKIP_ROM   0x3C

#include <zephyr/drivers/w1.h>

This command allows the bus master to address all devices on the bus and then switch them to overdrive speed.

W1_CMD_READ_ROM

#define W1_CMD_READ_ROM   0x33

#include <zephyr/drivers/w1.h>

This command allows the bus master to read the ROM code from a single slave device.

This command should be used when there is only a single slave device on the bus.

W1_CMD_RESUME

#define W1_CMD_RESUME   0xA5

#include <zephyr/drivers/w1.h>

This command allows the bus master to resume a previous read out from where it left off.

W1_CMD_SEARCH_ALARM

#define W1_CMD_SEARCH_ALARM   0xEC

#include <zephyr/drivers/w1.h>

This command allows the bus master to identify which devices have experienced an alarm condition.

W1_CMD_SEARCH_ROM

#define W1_CMD_SEARCH_ROM   0xF0

#include <zephyr/drivers/w1.h>

This command allows the bus master to discover the addresses (i.e., ROM codes) of all slave devices on the bus.

W1_CMD_SKIP_ROM

#define W1_CMD_SKIP_ROM   0xCC

#include <zephyr/drivers/w1.h>

This command allows the bus master to read the slave devices without providing their ROM code.

W1_CRC16_POLYNOMIAL

#define W1_CRC16_POLYNOMIAL   0xa001

#include <zephyr/drivers/w1.h>

Polynomial used to calculate the 1-Wire 16-bit crc.

W1_CRC16_SEED

#define W1_CRC16_SEED   0x0000

#include <zephyr/drivers/w1.h>

Seed value used to calculate the 1-Wire 16-bit crc.

W1_CRC8_POLYNOMIAL

#define W1_CRC8_POLYNOMIAL   0x8C

#include <zephyr/drivers/w1.h>

Polynomial used to calculate the 1-Wire 8-bit crc.

W1_CRC8_SEED

#define W1_CRC8_SEED   0x00

#include <zephyr/drivers/w1.h>

Seed value used to calculate the 1-Wire 8-bit crc.

W1_ROM_INIT_ZERO

#define W1_ROM_INIT_ZERO

#include <zephyr/drivers/w1.h>

Value:

        {                                                       \
                .family = 0, .serial = { 0 }, .crc = 0,         \
        }

Initialize all w1_rom struct members to zero.

W1_SEARCH_ALL_FAMILIES

#define W1_SEARCH_ALL_FAMILIES   0x00

#include <zephyr/drivers/w1.h>

This flag can be passed to searches in order to not filter on family ID.

Typedef Documentation

w1_search_callback_t

typedef void(* w1_search_callback_t) (struct w1_rom rom, void *user_data)

#include <zephyr/drivers/w1.h>

Define the application callback handler function signature for searches.

Parameters

rom	found The ROM of the found slave.
user_data	User data provided to the w1_search_bus() call.

Function Documentation

w1_crc16()

static uint16_t w1_crc16 ( const uint16_t seed, const uint8_t * src, const size_t len )

inlinestatic

#include <zephyr/drivers/w1.h>

Compute 1-Wire variant of CRC 16.

The 16-bit 1-Wire crc variant is using the reflected polynomial function X^16 + X^15 * + X^2 + 1 with the initial value set to 0x0000. See also APPLICATION NOTE 27: "UNDERSTANDING AND USING CYCLIC REDUNDANCY CHECKS WITH MAXIM 1-WIRE AND IBUTTON PRODUCTS" https://www.analog.com/en/resources/technical-articles/understanding-and-using-cyclic-redundancy-checks-with-maxim-1wire-and-ibutton-products.html

Parameters

	seed	Init value for the CRC, it is usually set to 0x0000.
[in]	src	Input bytes for the computation.
	len	Length of the input in bytes.

Return values

crc	The computed CRC16 value.

w1_crc8()

static uint8_t w1_crc8 ( const uint8_t * src, size_t len )

inlinestatic

#include <zephyr/drivers/w1.h>

Compute CRC-8 chacksum as defined in the 1-Wire specification.

The 1-Wire of CRC 8 variant is using 0x31 as its polynomial with the initial value set to 0x00. This CRC is used to check the correctness of the unique 56-bit ROM.

Parameters

[in]	src	Input bytes for the computation.
	len	Length of the input in bytes.

Return values

crc	The computed CRC8 value.

w1_match_rom()

int w1_match_rom	(	const struct device *	dev,
		const struct w1_slave_config *	config )

#include <zephyr/drivers/w1.h>

Select a specific slave by broadcasting a selected ROM.

This routine allows the 1-Wire bus master to select a slave identified by its unique ROM, such that the next command will target only this single selected slave.

This command is only necessary in multidrop environments, otherwise the Skip ROM command can be issued. Once a slave has been selected, to reduce the communication overhead, the resume command can be used instead of this command to communicate with the selected slave.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	config	Pointer to the slave specific 1-Wire config.

Return values

0	If successful.
-ENODEV	In case no slave responds to reset.
-errno	Other negative error code on error.

w1_read_rom()

int w1_read_rom	(	const struct device *	dev,
		struct w1_rom *	rom )

#include <zephyr/drivers/w1.h>

Read Peripheral 64-bit ROM.

This procedure allows the 1-Wire bus master to read the peripherals’ 64-bit ROM without using the Search ROM procedure. This command can be used as long as not more than a single peripheral is connected to the bus. Otherwise data collisions occur and a faulty ROM is read.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[out]	rom	Pointer to the ROM structure.

Return values

0	If successful.
-ENODEV	In case no slave responds to reset.
-errno	Other negative error code in case of invalid crc and communication errors.

w1_reset_select()

int w1_reset_select	(	const struct device *	dev,
		const struct w1_slave_config *	config )

#include <zephyr/drivers/w1.h>

In single drop configurations use Skip Select command, otherwise use Match ROM command.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	config	Pointer to the slave specific 1-Wire config.

Return values

0	If successful.
-ENODEV	In case no slave responds to reset.
-errno	Other negative error code on error.

w1_resume_command()

int w1_resume_command

(

const struct device *

dev

)

#include <zephyr/drivers/w1.h>

Select the slave last addressed with a Match ROM or Search ROM command.

This routine allows the 1-Wire bus master to re-select a slave device that was already addressed using a Match ROM or Search ROM command.

Parameters

dev	Pointer to the device structure for the driver instance.

Return values

0	If successful.
-ENODEV	In case no slave responds to reset.
-errno	Other negative error code on error.

w1_rom_to_uint64()

static uint64_t w1_rom_to_uint64 ( const struct w1_rom * rom )

inlinestatic

#include <zephyr/drivers/w1.h>

Function to convert a w1_rom struct to an uint64_t.

Parameters

[in]

rom

Pointer to the ROM struct.

Return values

rom64

The ROM converted to an unsigned integer in endianness.

w1_search_alarm()

static int w1_search_alarm ( const struct device * dev, w1_search_callback_t callback, void * user_data )

inlinestatic

#include <zephyr/drivers/w1.h>

Search for 1-Wire slaves with an active alarm.

This routine searches 1-Wire slaves on the bus, which currently have an active alarm.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
	callback	Application callback handler function to be called for each found slave.
[in]	user_data	User data to pass to the application callback handler function.

Return values

slave_count	Number of slaves found.
-errno	Negative error code on error.

w1_search_bus()

int w1_search_bus	(	const struct device *	dev,
		uint8_t	command,
		uint8_t	family,
		w1_search_callback_t	callback,
		void *	user_data )

#include <zephyr/drivers/w1.h>

Search 1-wire slaves on the bus.

This function searches slaves on the 1-wire bus, with the possibility to search either all slaves or only slaves that have an active alarm state. If a callback is passed, the callback is called for each found slave.

The algorithm mostly follows the suggestions of https://www.analog.com/en/resources/app-notes/1wire-search-algorithm.html

Note: Filtering on families is not supported.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
	command	Can either be W1_SEARCH_ALARM or W1_SEARCH_ROM.
	family	W1_SEARCH_ALL_FAMILIES searcheas all families, filtering on a specific family is not yet supported.
	callback	Application callback handler function to be called for each found slave.
[in]	user_data	User data to pass to the application callback handler function.

Return values

slave_count	Number of slaves found.
-errno	Negative error code on error.

w1_search_rom()

static int w1_search_rom ( const struct device * dev, w1_search_callback_t callback, void * user_data )

inlinestatic

#include <zephyr/drivers/w1.h>

Search for 1-Wire slave on bus.

This routine can discover unknown slaves on the bus by scanning for the unique 64-bit registration number.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
	callback	Application callback handler function to be called for each found slave.
[in]	user_data	User data to pass to the application callback handler function.

Return values

slave_count	Number of slaves found.
-errno	Negative error code on error.

w1_skip_rom()

int w1_skip_rom	(	const struct device *	dev,
		const struct w1_slave_config *	config )

#include <zephyr/drivers/w1.h>

Select all slaves regardless of ROM.

This routine sets up the bus slaves to receive a command. It is usually used when there is only one peripheral on the bus to avoid the overhead of the Match ROM command. But it can also be used to concurrently write to all slave devices.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	config	Pointer to the slave specific 1-Wire config.

Return values

0	If successful.
-ENODEV	In case no slave responds to reset.
-errno	Other negative error code on error.

w1_uint64_to_rom()

static void w1_uint64_to_rom ( const uint64_t rom64, struct w1_rom * rom )

inlinestatic

#include <zephyr/drivers/w1.h>

Function to write an uint64_t to struct w1_rom pointer.

Parameters

	rom64	Unsigned 64 bit integer representing the ROM in host endianness.
[out]	rom	The ROM struct pointer.

w1_write_read()

int w1_write_read	(	const struct device *	dev,
		const struct w1_slave_config *	config,
		const uint8_t *	write_buf,
		size_t	write_len,
		uint8_t *	read_buf,
		size_t	read_len )

#include <zephyr/drivers/w1.h>

Write then read data from the 1-Wire slave with matching ROM.

This routine uses w1_reset_select to select the given ROM. Then writes given data and reads the response back from the slave.

Parameters

[in]	dev	Pointer to the device structure for the driver instance.
[in]	config	Pointer to the slave specific 1-Wire config.
[in]	write_buf	Pointer to the data to be written.
	write_len	Number of bytes to write.
[out]	read_buf	Pointer to storage for read data.
	read_len	Number of bytes to read.

Return values

0	If successful.
-ENODEV	In case no slave responds to reset.
-errno	Other negative error code on error.