HT1382_1105 HOLTEK [Holtek Semiconductor Inc], HT1382_1105 Datasheet - Page 12

• Manufacturer Part Number: HT1382_1105
• Description: I2C/3-Wire Real Time Clock
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

Rev. 1.40
Real Time Clock Register
12/24 Hour Mode
AM/PM Mode
Leap Years
Clock HALT Bit - CH
Write Protect Bit - WP
Battery Enable Bit - BE
Alarm Interrupt Bit - AI
Auto Reset Enable Bit - ARE
EEPROM Write Enable Bit - EWE
The RTC register stores the Year, Day, Month, Date, Hours, Minutes and, Second data in BCD format.
Bit D7 of the hour register is defined as the 12-hour or 24-hours mode select bit. If the bit is 1 , the
RTC uses a 24-hour format. If 0 , the RTC uses a 12-hour format. The default value is 0 .
There are two function for the D5 bit in the hour register which is determined by the D7 bit. In the
12-hour mode the bit is used for AM/PM selection. When D5 is 1 , it will be PM, otherwise it will be
AM. In the 24-hour mode, the bit is used to set the second 10-hour bit(20~23 hours).
Leap years add an extra day for February 29 and are defined as those years that are divisible by 4. The
device will provide automatic correction for leap years until year 2099.
This bit enables/disables the oscillator. The CH bit is set high to disable the oscillator and cleared to
zero is enable it. The default value is define as 1 .
The WP bit is set high to prevent data writes and cleared to zero to allow data to be written. The default
value is define as 1 .
When the device enters the battery backup mode, the BE bit is set to 1 . This bit can be cleared to 0
either manually by the user or automatically reset by the ARE pin. Only a 0 an be written to this bit,
not a 1 .
When the RTC register values match the alarm register values, the AI bit will be set to 1 . This bit can
be reset to 0 either manually by the user or automatically reset by the ARE pin. Only a 0 an be
written to this bit, not a 1 . The AI bit will be set by an alarm occurring during a read operation ad will
remain set until after the read operation is complete.
This bit enables/disables the automatic reset of the BE and AI status bits only. When ARE is set to 1 ,
BE and AI will be reset to 0 after reading these registers. When ARE is cleared to 0 , the user must
manually reset the BE and AI bits.
When EWE is cleared to 0 , the EEPROM is read only, and the user can not write data to the
EEPROM. When EWE is set to 1 , the user can write data to the EEPROM. Before writing data to the
EEPROM, this bit must be set to 1 .
12
I
2
C/3-Wire Real Time Clock
HT1382
May 27, 2011