V3022 EMMICRO [EM Microelectronic - MARIN SA], V3022 Datasheet - Page 11

• Manufacturer Part Number: V3022
• Description: Very Low Power 8-Bit 32 kHz RTC Module with Digital Trimming and High Level Integration
• Manufacturer: EMMICRO [EM Microelectronic - MARIN SA]

Reading the Clock
Alarm
An alarm date and time may be preset in RAM addresses
30 to 34 hex. The alarm function can be activated by
setting the alarm enable / disable bit (addr. 00 hex, bit 2).
Once enabled the preset alarm time and date are
compared, every internal time update cycle (10 ms), with
the clock parameters in the reserved clock area. When
the clock parameters equal the alarm parameters the
alarm flag (addr. 01 hex, bit 5) is set. If the alarm mask bit
(addr. 01 hex, bit 1) is set, the IRQ pin goes active. The
alarm flag indicates to software the source of the interrupt.
interrupt by clearing the alarm flag.
enabled, and an alarm address set to FF hex, this
Copyright © 2004, EM Microelectronic-Marin SA
IRQ will remain active until software acknowledges the
[Pin 7 = A/D]
A/D = 0
A/D = 1
A/D = 0
A/D = 1
A/D = 0
A/D = 1
A/D = 0
A/D = 1
R
copy the timer parameters from
Read 1/100 sec. data from the
Write sec. address (21 hex) to
Write min. address (22 hex) to
the reserved clock area to the
Read sec. data from the RAM
Read min. data from the RAM
Read data from the V3022 to
Write 1/100 sec. address (20
(addr. F1 hex) to the V3022
RAM. A data read has no
Write clock command
hex) to the V3022
significance
the V3022
the V3022
Start
RAM
End
If the alarm is
Fig. 9
Setting the Timer (Time Set Lock Bit = 0)
Note : Commands are only valid as commands when the
as in the last box of Fig. 8, serves only to activate the
V3022 write pin which determines the direction of transfer.
parameters is not compared with the associated clock
parameter. Thus it is possible to achieve a repeat feature
where an alarm occurs every programmed number of
seconds, or seconds and minutes, or seconds, minutes
and hours. The V3022 pulls the open drain IRQ line
active low during standby when an alarm interrupt occurs.
If the 12/24 hour mode is changed then the alarm hours
must be re-initialised.
Note : The user should ensure that a time lapse of at least
60 microseconds exists between the falling edge of the
IRQ and the clearing of the alarm flag.
A /D line is low. Writing F2 hex with the A /D line high,
11
[Pin 7 = A/D]
A/D = 0
A/D = 1
A/D = 0
A/D = 1
A/D = 0
A/D = 1
A/D = 0
A/D = 1
A/D = 0
A/D = 1
Write hours address (43 hex) to
RAM to the reversed timer area
Write timer command (addr. F2
copy the timer parameters from
Write sec. address (41 hex) to
Write min. address (42 hex) to
Write 1/100 sec. address (40
Write hours data to the RAM
Write F2 hex to the V3022 to
Write 1/100 sec. data to the
Write sec. data to the RAM
Write min. data to the RAM
hex) to the V3022
hex) to the V3022
the V3022
the V3022
the V3022
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RAM
Start
End
V3022
Fig. 10