Micro crystal RV-8063-C7, Руководство по применению

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Micro Crystal
Ultra Small Real-Time Clock Module with SPI-Bus Interface RV-8063-C7
October 2018 27/58 Rev. 1.1
COUNTDOWN TIMER FUNCTION 4.7.
TIMER FLAG TF 4.7.1.
The Timer Flag (bit TF) is set logic 1 on the first trigger of the Countdown Timer or the MI and HMI Interrupt. The
purpose of the flag is to allow the controlling system to interrogate what caused the interrupt: Timer/MI/HMI or
Alarm. The flag can be read and cleared by command.
The status of the Timer Flag TF can affect the
INT
̅̅̅̅̅
pulse generation depending on the setting of TI_TP (see TIMER
REGISTERS, 11h
– Timer Mode):
TIMER INTERRUPT MODE TI_TP 4.7.2.
When Interrupt is in Interval Mode (TI_TP = 0):

only one Interrupt after the first countdown when TF is not cleared

the
INT
̅̅̅̅̅
generation follows the TF flag

TF stays set until it is cleared

If TF is not cleared before the next coming interrupt, no
INT
̅̅̅̅̅
is generated
When Interrupt is in Timer Pulse Mode (TI_TP = 1):

the Countdown Timer runs in a repetitive loop and keeps generating periodic interrupts

an
INT
̅̅̅̅̅
pulse is generated independent of the status of the Timer Flag TF

TF stays set until it is cleared.

TF does not affect
INT
̅̅̅̅̅
PULSE GENERATOR 2 4.7.3.
When the Timer Pulse Mode is activated (TI_TP = 1) the Pulse Generator 2 for the Countdown Timer Interrupt
uses an internal clock and is dependent on the selected Timer Clock Frequency for the countdown timer and on the
Timer Value. As a consequence, the width of the interrupt pulse varies (see following Table). The pulse widths are
not affected by the Offset Mode (bit MODE). TF and
INT
̅̅̅̅̅
become active simultaneously.
INT
̅̅̅̅̅
pulse width when using Countdown Timer:
Timer Clock Frequency
INT
̅̅̅̅̅
pulse width
Timer Value = 1
(1)
Timer Value > 1
(1)
4.096 kHz 122 µs 244 µs
64 Hz 7.812 ms 15.625 ms
1 Hz 15.625 ms 15.625 ms
1/60 Hz 15.625 ms 15.625 ms
(1)
Timer Value = loaded countdown value. Timer stops when Timer Value = 0.