Functions
uint8_t	crc_check (uint8_t *buffer, uint8_t len)
	Performs a CRC (Cyclic Redundancy Check) over a buffer. More...

ssize_t	one_wire_address (uint8_t *romcode)
	Used for addressing a specific device connected to the 1-Wire bus. Usually used after a one_wire_reset() command. More...

int	one_wire_config (void)
	Initializes and configures the 1-Wire interface. More...

ssize_t	one_wire_read (uint8_t *rxbuf, uint8_t len)
	Reads from the 1-Wire bus determined number of bytes. More...

ssize_t	one_wire_read_byte (uint8_t *rxbyte)
	Reads one byte from the 1-Wire bus. More...

ssize_t	one_wire_read_rom (uint8_t *romcode)
	If there is only one device connected to the 1-Wire bus, reads its ROM code. This ROM is CRC8 checked before reporting a success. More...

ssize_t	one_wire_reset (void)
	Performs a reset on the 1-Wire bus. More...

ssize_t	one_wire_search (uint8_t *rombuf, uint8_t len)
	Performs the 1-Wire search algorithm and store ROM codes found. More...

uint8_t	one_wire_single_bit_rx (void)
	Reads 1 bit from the 1-Wire bus. More...

uint8_t	one_wire_single_bit_tx (uint8_t bit)
	Sends 1 bit over the 1-Wire bus. More...

ssize_t	one_wire_skip_rom (void)
	Used when only one device is connected to the 1-Wire bus, so sending 32-bit ROM code is unnecessary. Usually used after a one_wire_reset() command. More...

void	one_wire_spp_enable (bool_t val)
	Activates or deactivates the strong pull-up (if enabled) on the 1-Wire bus. More...

ssize_t	one_wire_write (const uint8_t *txbuf, uint8_t len)
	Sends over the 1-Wire bus a buffer with a determined length. More...

ssize_t	one_wire_write_byte (uint8_t byte)
	Sends 1 byte over the 1-Wire bus. More...

Detailed Description

Platform-specific layer provides a consistent 1-Wire API to upper layers of the driver.

1-Wire API Overview

1-Wire is a device communications bus system designed by Dallas Semiconductor Corp. that provides low-speed data, signaling, and power over a single signal.

This API contains the functions to configure and control a 1 Wire bus by bit-banging a GPIO of the programmable XBee devices.

1-Wire functions:

Platform-specific layer provides a consistent MACROS API to upper layers of the driver.

1-Wire ROM-Commands

The 1-Wire protocol has 5 generic ROM-Commands that may be used with one_wire_write() and one_wire_write_byte() functions:

ONE_WIRE_READ_ROM : Read rom of device (only works when there is a unique device conected to the bus).
ONE_WIRE_MATCH_ROM : Master will transfer the ROM of desired device, devices with different ROM will stay idle.
ONE_WIRE_SEARCH_ROM : Starts a ROM search over the 1-Wire bus.
ONE_WIRE_SKIP_ROM : All devices will listen to command regardless their ROM, use with care.
ONE_WIRE_AlARM_SEARCH: Similar to search ROM algorithm but only devices with a triggered alarm will answer.

Function Documentation

uint8_t crc_check	(	uint8_t *	buffer,
		uint8_t	len
	)

Performs a CRC (Cyclic Redundancy Check) over a buffer.

Parameters

[in]	buffer	the buffer which will be checked.
[in]	len	the number of bytes to be considered.

Return values

int	the CRC result.

ssize_t one_wire_address ( uint8_t * romcode )

Used for addressing a specific device connected to the 1-Wire bus. Usually used after a one_wire_reset() command.

Parameters

[in] romcode the ROM code of the device to be addressed.

Return values

ssize_t	0 on success.
ssize_t	<0 if there is an error.

int one_wire_config ( void )

Initializes and configures the 1-Wire interface.

Return values

0	on success.

ssize_t one_wire_read	(	uint8_t *	rxbuf,
		uint8_t	len
	)

Reads from the 1-Wire bus determined number of bytes.

Parameters

[out]	rxbuf	the buffer where the received bytes will be stored.
[in]	len	the number of bytes to be read.

Return values

int	0 on success.
int	<0 if there is an error while reading.

ssize_t one_wire_read_byte ( uint8_t * rxbyte )

Reads one byte from the 1-Wire bus.

Parameters

[out] rxbyte the buffer where the received byte will be stored.

Return values

int	0 on success.

ssize_t one_wire_read_rom ( uint8_t * romcode )

If there is only one device connected to the 1-Wire bus, reads its ROM code. This ROM is CRC8 checked before reporting a success.

Parameters

[out] romcode the buffer where the ROM code will be stored.

Return values

int	0 on success.
int	<0 if there is an error while reading.

ssize_t one_wire_reset ( void )

Performs a reset on the 1-Wire bus.

Return values

0	on success.
<0	if there is an error

ssize_t one_wire_search	(	uint8_t *	rombuf,
		uint8_t	len
	)

Performs the 1-Wire search algorithm and store ROM codes found.

Parameters

[in]	rombuf	the buffer where ROM codes will be stored (should be big enough to store maximum number of devices (e.g.: rombuf[8 * len]).
[in]	len	the maximum number of device that can be found.

Return values

int	number of devices found.
<0	if there is any error while looking for devices.

uint8_t one_wire_single_bit_rx ( void )

Reads 1 bit from the 1-Wire bus.

Return values

bit read.

uint8_t one_wire_single_bit_tx ( uint8_t bit )

Sends 1 bit over the 1-Wire bus.

Parameters

[in] bit bit to be transferred.

Return values

0	on success.

ssize_t one_wire_skip_rom ( void )

Used when only one device is connected to the 1-Wire bus, so sending 32-bit ROM code is unnecessary. Usually used after a one_wire_reset() command.

Return values

ssize_t	0 on success.
ssize_t	<0 if there is an error while reading.

void one_wire_spp_enable ( bool_t val )

Activates or deactivates the strong pull-up (if enabled) on the 1-Wire bus.

Parameters

[in] val 1 for enabling, 0 for disabling.

Return values

none

ssize_t one_wire_write	(	const uint8_t *	txbuf,
		uint8_t	len
	)

Sends over the 1-Wire bus a buffer with a determined length.

Parameters

[in]	txbuf	the buffer containing the bytes to be transferred. Frist byte may be 1-Wire ROM-Commands or device-specific commands.
[in]	len	the number of bytes to be transferred.

Return values

int	0 on success.
int	<0 if there is an error while transferring.

ssize_t one_wire_write_byte ( uint8_t byte )

Sends 1 byte over the 1-Wire bus.

Parameters

[in] byte byte to be transferred. This may be 1-Wire ROM-Commands or device-specific commands.

Return values

int	0 on success.

Functions

Detailed Description

1-Wire API Overview

1-Wire ROM-Commands

Function Documentation