RTC - 4543 SA/SB

6.Timer Data Organization

The counter data is BCD code.

The timer automatically adjusts for different month lengths and for leap year.

The time is indicated in 24-hour format.

Writes and reads are both performed on an LSB-first basis.

 

MSB

 

 

 

 

 

 

LSB

Second

FDT

s40

s20

s10

s8

s4

s2

s1

( 0 to 59 )

 

 

 

 

 

 

 

 

Minutes

 

 

 

 

 

 

 

 

*

mi40

mi20

mi10

mi8

mi4

mi2

mi1

( 0 to 59 )

 

 

 

 

 

 

 

 

Hour ( 0 to 23 )

 

 

 

 

 

 

 

 

*

*

h20

h10

h8

h4

h2

h1

 

Day of the week

 

 

 

 

 

 

 

 

 

 

 

 

*

w4

w2

w1

( 1 to 7 )

 

 

 

 

 

 

 

 

 

 

 

 

Day ( 1 to 31 )

 

 

 

 

 

 

 

 

*

*

d20

d10

d8

d4

d2

d1

 

Month ( 1 to 12 )

 

 

 

 

 

 

 

 

TM

*

*

mo10

mo8

mo4

mo2

mo1

 

Year ( 0 to 99 )

 

 

 

 

 

 

 

 

y80

y40

y20

y10

y8

y4

y2

y1

 

*bits: Any data may be written to these bits.

FDT bit: Supply voltage detection bit

This bit is set to “1” when voltage of 1.7 ± 0.3 V or less is detected between VDD and GND.

The FDT bit is cleared if all of the digits up to the year digits are read.

Although this bit can be both read and written, normally set this bit to “0”.

VDD VDET

 

0.5 s

 

0.5 s

 

 

 

 

 

 

 

Detection pulse

Mode

Read

FDT bit

The supply voltage detection circuit monitors the supply voltage once every 0.5 seconds; if the supply voltage is lower than the detection voltage value, the FDT bit is set to “1”.

TM bit: This is a test bit for SEIKO-EPSON’s use. Always set this bit to “0”.

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