DS1904 Real-Time Clock

Functions
uint32_t	ds1904_date_convert (tm_rtc_t date)
	Converts a date to epoch time. More...
ssize_t	ds1904_date_update (uint8_t *rom)
	Reads the RTC time-register and updates global time. More...
void	ds1904_get_date (tm_rtc_t *date)
	Returns current date and time from RTC. More...
ssize_t	ds1904_read (uint8_t *rom, uint8_t *config, uint32_t *time)
	Reads configuration and time registers. More...
ssize_t	ds1904_set (uint8_t *rom, bool_t enable)
	Enables or disables RTC's oscillator maintaining current time value. More...
ssize_t	ds1904_write (uint8_t *rom, uint8_t config, uint32_t time)
	Writes configuration and time registers. More...

Detailed Description

DS1904 API Overview

This API contains the functions to configure and control a DS1904 Real-Time-Clock over a 1-Wire bus.

• DS1904 functions:
  • ds1904_read()
  • ds1904_write()
  • ds1904_set()
  • ds1904_date_convert()
  • ds1904_date_update()
  • ds1904_get_date()

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

DS1904 RTC Macros

The DS1904 has 2 specific commands that are defined as the following macros:

• DS1904_READ_CLOCK : Allows master to read the current time value and configuration resgister.
• DS1904_WRITE_CLOCK : Allows master to write time and configuration resgiers. Also there are defined the two combinations of configuration register to enable or disable internal oscillator:
• DS1904_OSC_ENABLE : Enables RTC oscillator.
• DS1904_OSC_DISABLE : Disables.

Function Documentation

uint32_t ds1904_date_convert

(

tm_rtc_t

date

)

Converts a date to epoch time.

Parameters

[in]

date

address where ROM of device is stored.

Return values

date	in epoch time (0 for 0:00 of 1/1/1970).

ssize_t ds1904_date_update

(

uint8_t *

rom

)

Reads the RTC time-register and updates global time.

Parameters

[in]

rom

address where ROM of device is stored. NULL if only one device is connected to the 1-Wire bus.

Return values

0	on success.
<0	if there is any error.

void ds1904_get_date

(

tm_rtc_t *

date

)

Returns current date and time from RTC.

Parameters

[out]

date

address where current date will be written.

Return values

void

ssize_t ds1904_read	(	uint8_t *	rom,
		uint8_t *	config,
		uint32_t *	time
	)

Reads configuration and time registers.

Parameters

[in]	rom	address where ROM of device is stored. NULL if only one device is connected to the 1-Wire bus.
[out]	config	address where configuration register will be stored.
[out]	time	address where time-count register will be stored.

Return values

0	on success.
<0	if there is any error.

ssize_t ds1904_set	(	uint8_t *	rom,
		bool_t	enable
	)

Enables or disables RTC's oscillator maintaining current time value.

Parameters

[in]	rom	address where ROM of device is stored. NULL if only one device is connected to the 1-Wire bus.
[in]	enable	TRUE for enabling and FALSE for disabling.

Return values

0	on success.
<0	if there is any error.

ssize_t ds1904_write	(	uint8_t *	rom,
		uint8_t	config,
		uint32_t	time
	)

Writes configuration and time registers.

Parameters

[in]	rom	address where ROM of device is stored. NULL if only one device is connected to the 1-Wire bus.
[in]	config	configuration register to be written.
[in]	time	time-count register to be written.

Return values

0	on success.
<0	if there is any error.