Datasheet

MCP79410/MCP79411/MCP79412
DS20002266E-page 12  2010-2013 Microchip Technology Inc.
5.0 TIME AND DATE REGISTERS
The MCP7941X Serial Real-Time Clock/Calendar uses
a low-power external 32.768 kHz crystal to maintain the
time and date in a system.
The Real-Time Clock using an external oscillator tracks
the time and date with separate registers for hours,
minutes, seconds. The MCP7941X also has separate
calendar registers for date, month, year and day of the
week. The calendar adjusts automatically for months
with less than 31 days and also calculates the leap year
until 2099.
The Time and Date registers store the current time and
date as BCD. Using an external backup supply, the
time can be maintained during a V
CC power-fail.
REGISTER 5-1: SECONDS 0X00
R/W-0 R/W-0 R/W-0
ST 10 Seconds Seconds
bit 7 bit 6 bit 4 bit 3 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set “0” = Bit is clear “X” = Bit is unknown
bit 7 ST: Start Oscillator bit
1 = Oscillator enabled
0 = Oscillator disabled; The oscillator should be disabled before setting the Time registers.
bit 6-4 10 SECONDS <6:4>: Binary-Coded Decimal Value of Second’s Tens Digit
Contains a value from 0 to 5
bit 3-0 SECONDS<3:0>: Binary-Coded Decimal Value of Second’s Ones Digit
Contains a value from 0 to 9
REGISTER 5-2: MINUTES 0X01
U-0 R/W-0 R/W-0
— 10 Minutes Minutes
bit 7 bit 6 bit 4 bit 3 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set “0” = Bit is clear “X” = Bit is unknown
bit 7 Unimplemented: Read as ‘0’
bit 6-4 10 MINUTES<2:0>: Binary-Coded Decimal Value of Minute’s Tens Digit
Contains a value from 0 to 5
bit 3-0 MINUTES<3:0>: Binary-Coded Decimal Value of Minute’s Ones Digit
Contains a value from 0 to 9