• 7 •

Table 9 Value descriptions for bits AF and TF

R/W

Bit: AF

Bit: TF

Value

Description

Value

Description

Read

0

alarm flag inactive

0

timer flag inactive

1

alarm flag active

1

timer flag active

Write

0

alarm flag is cleared

0

timer flag is cleared

1

alarm flag remains unchanged

1

timer flag remains unchanged

2.7.3 Seconds, Minutes and Hours registers

Table 10: Seconds/VL register bits description

02H

Symbol

Description

b7

VL

VL = 0: reliable clock/calendar information is guaranteed;

VL = 1: reliable clock/calendar information is no longer guaranteed.

b6..0

<seconds>

These bits represent the current seconds value coded in BCD format; value

=00to 59.

Example: <seconds> = 101 1001, represents the value 59 s.

Table 11 Minutes register bits description

03H

Symbol

Description

b7

-

not implemented

b6..0

<minutes>

These bits represent the current minutes value coded in BCD

format; value = 00 to 59.

Table 12 Hours register bits description

04H

Symbol

Description

b7..6

-

not implemented

b5..0

<hours>

These bits represent the current hours value coded in BCD format; value = 00

to 23.

2.7.4 Days, Weekdays, Months/Century and Years registers

Table 13 Days register bits description

05H

Symbol

Description

b7..6

-

not implemented

b5..0

<days>

These bits represent the current day value coded in BCD format; value = 01 to

31.

HM8563 compensates for leap years by adding a 29th day to Febr uary if the year

counter contains a value which is exactly divisible by 4, including the year ‘00’.

HM8563