DS18x20 temperature sensor

group LWOW_DEVICE_DS18x20

Device driver for DS18x20 temperature sensor.

Note

Functions with _raw suffix do no implement locking mechanism when used with operating system.

Defines

LWOW_DS18X20_ALARM_DISABLE: Disable alarm temperature

LWOW_DS18X20_ALARM_NOCHANGE: Do not modify current alarm settings

LWOW_DS18X20_TEMP_MIN: Minimum temperature

LWOW_DS18X20_TEMP_MAX: Maximal temperature

LWOW_DS18X20_CMD_ALARM_SEARCH: Alarm Search Command

LWOW_DS18X20_CMD_CONVERT_T: Convert T Command

Functions

uint8_t lwow_ds18x20_start_raw(lwow_t *const owobj, const lwow_rom_t *const rom_id)

Start temperature conversion on specific (or all) devices.

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address to start measurement for. Set to NULL to start measurement on all devices at the same time

Returns

1 on success, 0 otherwise

uint8_t lwow_ds18x20_start(lwow_t *const owobj, const lwow_rom_t *const rom_id)

Start temperature conversion on specific (or all) devices.

Note

This function is thread-safe

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address to start measurement for. Set to NULL to start measurement on all devices at the same time

Returns

1 on success, 0 otherwise

uint8_t lwow_ds18x20_read_raw(lwow_t *const owobj, const lwow_rom_t *const rom_id, float *const temp_out)

Read temperature previously started with lwow_ds18x20_start.

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address to read data from
temp_out – [out] Pointer to output float variable to save temperature

Returns

1 on success, 0 otherwise

uint8_t lwow_ds18x20_read(lwow_t *const owobj, const lwow_rom_t *const rom_id, float *const temp_out)

Read temperature previously started with lwow_ds18x20_start.

Note

This function is thread-safe

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address to read data from
temp_out – [out] Pointer to output float variable to save temperature

Returns

1 on success, 0 otherwise

uint8_t lwow_ds18x20_set_resolution_raw(lwow_t *const owobj, const lwow_rom_t *const rom_id, const uint8_t bits)

Set resolution for DS18B20 sensor.

Note

DS18S20 has fixed 9-bit resolution

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address to set resolution
bits – [in] Number of resolution bits. Possible values are 9 - 12

Returns

1 on success, 0 otherwise

uint8_t lwow_ds18x20_set_resolution(lwow_t *const owobj, const lwow_rom_t *const rom_id, const uint8_t bits)

Set resolution for DS18B20 sensor.

Note

DS18S20 has fixed 9-bit resolution

Note

This function is thread-safe

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address to set resolution
bits – [in] Number of resolution bits. Possible values are 9 - 12

Returns

1 on success, 0 otherwise

uint8_t lwow_ds18x20_get_resolution_raw(lwow_t *const owobj, const lwow_rom_t *const rom_id)

Get resolution for DS18B20 device.

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address to get resolution from

Returns

Resolution in units of bits (9 - 12) on success, 0 otherwise

uint8_t lwow_ds18x20_get_resolution(lwow_t *const owobj, const lwow_rom_t *const rom_id)

Get resolution for DS18B20 device.

Note

This function is thread-safe

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address to get resolution from

Returns

Resolution in units of bits (9 - 12) on success, 0 otherwise

uint8_t lwow_ds18x20_set_alarm_temp_raw(lwow_t *const owobj, const lwow_rom_t *const rom_id, int8_t temp_l, int8_t temp_h)

Set/clear temperature alarm high/low levels in units of degree Celcius.

Example usage would look something similar to:

//Set alarm temperature; low = 10°C, high = 30°C
lwow_ds18x20_set_alarm_temp(&ow, dev_id, 10, 30);
//Set alarm temperature; low = disable, high = no change
lwow_ds18x20_set_alarm_temp(&ow, dev_id, LWOW_DS18X20_ALARM_DISABLE, LWOW_DS18X20_ALARM_NOCHANGE);
//Set alarm temperature; low = no change, high = disable
lwow_ds18x20_set_alarm_temp(&ow, dev_id, LWOW_DS18X20_ALARM_NOCHANGE, LWOW_DS18X20_ALARM_DISABLE);
//Set alarm temperature; low = 10°C, high = 30°C
lwow_ds18x20_set_alarm_temp(&ow, dev_id, 10, 30);

Note

temp_h and temp_l are high and low temperature alarms and can accept different values:

-55 % 125, valid temperature range
LWOW_DS18X20_ALARM_DISABLE to disable temperature alarm (either high or low)
LWOW_DS18X20_ALARM_NOCHANGE to keep current alarm temperature (either high or low)

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address
temp_l – [in] Alarm low temperature
temp_h – [in] Alarm high temperature

Returns

1 on success, 0 otherwise

uint8_t lwow_ds18x20_set_alarm_temp(lwow_t *const owobj, const lwow_rom_t *const rom_id, int8_t temp_l, int8_t temp_h)

Set/clear temperature alarm high/low levels in units of degree Celcius.

Example usage would look something similar to:

//Set alarm temperature; low = 10°C, high = 30°C
lwow_ds18x20_set_alarm_temp(&ow, dev_id, 10, 30);
//Set alarm temperature; low = disable, high = no change
lwow_ds18x20_set_alarm_temp(&ow, dev_id, LWOW_DS18X20_ALARM_DISABLE, LWOW_DS18X20_ALARM_NOCHANGE);
//Set alarm temperature; low = no change, high = disable
lwow_ds18x20_set_alarm_temp(&ow, dev_id, LWOW_DS18X20_ALARM_NOCHANGE, LWOW_DS18X20_ALARM_DISABLE);
//Set alarm temperature; low = 10°C, high = 30°C
lwow_ds18x20_set_alarm_temp(&ow, dev_id, 10, 30);

Note

temp_h and temp_l are high and low temperature alarms and can accept different values:

-55 % 125, valid temperature range
LWOW_DS18X20_ALARM_DISABLE to disable temperature alarm (either high or low)
LWOW_DS18X20_ALARM_NOCHANGE to keep current alarm temperature (either high or low)

Note

This function is thread-safe

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address
temp_l – [in] Alarm low temperature
temp_h – [in] Alarm high temperature

Returns

1 on success, 0 otherwise

uint8_t lwow_ds18x20_get_alarm_temp_raw(lwow_t *const owobj, const lwow_rom_t *const rom_id, int8_t *temp_l, int8_t *temp_h)

Get the low and high temperature triggers for the alarm configuration.

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address
temp_l – [out] Pointer to output variable to write low temperature alarm trigger
temp_h – [out] Pointer to output variable to write high temperature alarm trigger

Returns

1 on success, 0 otherwise

uint8_t lwow_ds18x20_get_alarm_temp(lwow_t *const owobj, const lwow_rom_t *const rom_id, int8_t *temp_l, int8_t *temp_h)

Get the low and high temperature triggers for the alarm configuration.

Note

This function is thread-safe

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address
temp_l – [out] Pointer to output variable to write low temperature alarm trigger
temp_h – [out] Pointer to output variable to write high temperature alarm trigger

Returns

1 on success, 0 otherwise

lwowr_t lwow_ds18x20_search_alarm_raw(lwow_t *const owobj, lwow_rom_t *const rom_id)

Search for DS18x20 devices with alarm flag.

Note

To reset search, use lwow_search_reset function

Parameters

ow – [in] 1-Wire handle
rom_id – [out] Pointer to 8-byte long variable to save ROM

Returns

lwowOK on success, member of lwowr_t otherwise

lwowr_t lwow_ds18x20_search_alarm(lwow_t *const owobj, lwow_rom_t *const rom_id)

Search for DS18x20 devices with alarm flag.

Note

To reset search, use lwow_search_reset function

Note

This function is thread-safe

Parameters

ow – [in] 1-Wire handle
rom_id – [out] Pointer to 8-byte long variable to save ROM

Returns

lwowOK on success, member of lwowr_t otherwise

uint8_t lwow_ds18x20_is_b(lwow_t *const owobj, const lwow_rom_t *const rom_id)

Check if ROM address matches DS18B20 device.

Note

This function is reentrant

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address to test against DS18B20

Returns

1 on success, 0 otherwise

uint8_t lwow_ds18x20_is_s(lwow_t *const owobj, const lwow_rom_t *const rom_id)

Check if ROM address matches DS18S20 device.

Note

This function is reentrant

Parameters

ow – [in] 1-Wire handle
rom_id – [in] 1-Wire device address to test against DS18S20

Returns

1 on success, 0 otherwise

uint16_t lwow_ds18x20_get_temp_conversion_time(uint8_t resolution, uint8_t is_b)

Get temperature conversion time in units of milliseconds for a specific resolution.

Parameters

resolution – Resolution in bits
is_b – [in] Set to 1 for DS18B20, 0 otherwise

Returns

uint16_t