File syn_soft_onewire.c¶

FileList > drivers > syn_soft_onewire.c

Software bit-bang 1-Wire master implementation. More...

#include "../util/syn_assert.h"
#include "syn_soft_onewire.h"

Public Functions¶

Type	Name
void	syn_soft_onewire_init (SYN_SoftOneWire * ow, SYN_GPIO_Pin pin, uint32_t delay_loops) Initialize a 1-Wire bus instance.
uint8_t	syn_soft_onewire_read_byte (const SYN_SoftOneWire * ow) Read one byte LSB-first from the 1-Wire bus.
void	syn_soft_onewire_read_rom (const SYN_SoftOneWire * ow, uint8_t rom) Read an 8-byte ROM code from the bus (after READ ROM command).
bool	syn_soft_onewire_reset (const SYN_SoftOneWire * ow) Issue a 1-Wire reset pulse and detect device presence.
void	syn_soft_onewire_write_byte (const SYN_SoftOneWire * ow, uint8_t byte) Write one byte LSB-first onto the 1-Wire bus.
void	syn_soft_onewire_write_rom (const SYN_SoftOneWire * ow, const uint8_t rom) Write an 8-byte ROM code to the bus (for MATCH ROM command).

Public Static Functions¶

Type	Name
void	ow_delay (const SYN_SoftOneWire * ow, uint32_t us) NOP-loop delay.
void	ow_drive_low (const SYN_SoftOneWire * ow) Drive the 1-Wire pin low (open-drain).
uint8_t	ow_read_bit (const SYN_SoftOneWire * ow) Read a single bit from the 1-Wire bus.
void	ow_release (const SYN_SoftOneWire * ow) Release the 1-Wire pin (pullup takes over).
void	ow_write_bit (const SYN_SoftOneWire * ow, uint8_t bit) Write a single bit to the 1-Wire bus.

Detailed Description¶

Timing slots (standard speed): Write-0 slot : drive LOW 60 µs, release 10 µs recovery Write-1 slot : drive LOW 6 µs, release 64 µs recovery Read slot : drive LOW 6 µs, release, sample at ~9 µs, release 55 µs Reset pulse : drive LOW 480 µs, release, detect presence 60–240 µs, total reset cycle ~960 µs

All timing is approximated via a volatile NOP loop (delay_loops per µs). All I/O uses syn_port_gpio: output = drive low, input = release/read.

Public Functions Documentation¶

function syn_soft_onewire_init¶

Initialize a 1-Wire bus instance.

void syn_soft_onewire_init (
    SYN_SoftOneWire * ow,
    SYN_GPIO_Pin pin,
    uint32_t delay_loops
)

Parameters:

ow Bus handle to initialize. Must not be NULL.
pin GPIO pin for the data line.
delay_loops NOP loop iterations per µs at your CPU frequency. Use SYN_SOFT_ONEWIRE_LOOPS_PER_US(F_CPU) or SYN_SOFT_ONEWIRE_LOOPS_PER_US(16000000UL) for 16 MHz.

function syn_soft_onewire_read_byte¶

Read one byte LSB-first from the 1-Wire bus.

uint8_t syn_soft_onewire_read_byte (
    const SYN_SoftOneWire * ow
)

Parameters:

ow Initialized bus handle.

Returns:

Byte received.

function syn_soft_onewire_read_rom¶

Read an 8-byte ROM code from the bus (after READ ROM command).

void syn_soft_onewire_read_rom (
    const SYN_SoftOneWire * ow,
    uint8_t rom
)

Parameters:

ow Initialized bus handle.
rom Output buffer, must be at least 8 bytes.

function syn_soft_onewire_reset¶

Issue a 1-Wire reset pulse and detect device presence.

bool syn_soft_onewire_reset (
    const SYN_SoftOneWire * ow
)

Parameters:

ow Initialized bus handle.

Returns:

true if at least one device acknowledged (presence pulse detected), false if the bus is empty.

function syn_soft_onewire_write_byte¶

Write one byte LSB-first onto the 1-Wire bus.

void syn_soft_onewire_write_byte (
    const SYN_SoftOneWire * ow,
    uint8_t byte
)

Parameters:

ow Initialized bus handle.
byte Byte to transmit.

function syn_soft_onewire_write_rom¶

Write an 8-byte ROM code to the bus (for MATCH ROM command).

void syn_soft_onewire_write_rom (
    const SYN_SoftOneWire * ow,
    const uint8_t rom
)

Parameters:

ow Initialized bus handle.
rom 8-byte ROM code, LSB first.

Public Static Functions Documentation¶

function ow_delay¶

NOP-loop delay.

static void ow_delay (
    const SYN_SoftOneWire * ow,
    uint32_t us
)

Parameters:

ow 1-Wire instance.
us Microseconds to delay.

function ow_drive_low¶

Drive the 1-Wire pin low (open-drain).

static void ow_drive_low (
    const SYN_SoftOneWire * ow
)

Parameters:

ow 1-Wire instance.

function ow_read_bit¶

Read a single bit from the 1-Wire bus.

static uint8_t ow_read_bit (
    const SYN_SoftOneWire * ow
)

Parameters:

ow 1-Wire instance.

Returns:

Bit value (0 or 1).

function ow_release¶

Release the 1-Wire pin (pullup takes over).

static void ow_release (
    const SYN_SoftOneWire * ow
)

Parameters:

ow 1-Wire instance.

function ow_write_bit¶

Write a single bit to the 1-Wire bus.

static void ow_write_bit (
    const SYN_SoftOneWire * ow,
    uint8_t bit
)

Parameters:

ow 1-Wire instance.
bit Bit value (0 or 1).

The documentation for this class was generated from the following file src/syntropic/drivers/syn_soft_onewire.c