RV-8564 Datasheet, PDF (17/40 Pages) MICORO CRYSTAL SWITZERLAND – I2C-Bus Interface Real Time Clock

Micro Crystal
Real Time Clock / Calendar Module
RV-8564
9. DETAILED FUNCTIONAL DESCRIPTION
9.1. INTERRUPT OUTPUT
9.1.1.BITS TF AND AF
When an alarm occurs, AF is set to 1. Similarly, at the end of a timer countdown, TF is set to 1. These bits maintain
their value unit overwritten using the interface. If both timer and alarm are required in the application, the source of
the interrupt can be determined by reading these bits. To prevent one flag being overwritten while clearing another,
a logic AND in performed during a write access.
Note:
When bits TIE and AIE are disabled, pin INT will remain high-impedance.
9.1.2.BITS TIE AND AIE
These bits activate or deactivate the generation of an interrupt when TF or AF is asserted respectively. The
interrupt is the logical OR of these two conditions when both AIE and TIE are set.
9.1.3.COUNTDOWN TIMER INTERRUPT
The pulse generator for the countdown timer interrupt uses an internal clock and is dependent on the selected
source clock for the countdown timer and on the countdown value “n”. As a consequence, the width of the interrupt
pulse varies.
INT operation (bit TI/TP = 1)¹⁾
Source clock
4096 Hz
64 Hz
1 Hz
1_{/60 Hz}
INT period
n = 1²⁾
1_{/8192 s}
1_{/128 s}
1_{/64 s}
1_{/64 s}
n>1
1_{/4096 s}
1_{/64 s}
1_{/64 s}
1_{/64 s}
1) _{TF and INT become active simultaneously.}
2) _{n = loaded countdown value. Timer is stopped when n = 0.}
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