RV-3029 Datasheet, PDF (30/67 Pages) MICORO CRYSTAL SWITZERLAND – DTCXO Temperature Compensated Real Time Clock

Micro Crystal
DTCXO Temperature Compensated Real Time Clock / Calendar Module
RV-3029
Example Countdown Timer function with Timer in Auto Reload mode
In this example, the Countdown Timer is set to Automatic Reload Mode, the Countdown Timer value is set = “3”.
Automatic reload of the countdown value ,n’ requires 1 additional Timer Source Clock. This additional timer
source clock has no effect on the first Timer period but it has to be taken into account since it results in a Timer
duration of ,n+1’ for subsequent timer periods. The Interrupt signal ( INT ) is cleared by clearing the Timer Flag
“TF” = “0”.
1
TE
TAR
Timer Source
Clock Frequency
TD0 / TD1
Countdown Timer
Value
XX
03
02
01
Auto
Reload
03
02
01
Auto
Reload
03
02
TF
INT
TSC
n
TSC
n
n +1
2
3
4
53
4
1 _{Timer Source Clock Frequency TD0 / TD1 can only be modified when Timer is disabled “TE” = “0”}
Countdown Timer value ,n’ in “Timer Low” and “Timer High” only can be modified when Timer “TE” = “0”
and Timer Auto Reload “TAR” = “0” are both disabled.
2
Duration
of
first
Timer
Period
=
Source
n
Clock Frequency
The additional timer source clock for automatic reload of the countdown Timer value ,n’ has no effect on
the first Timer Period.
3 _{Timer Automatic Reload mode “TAR” requires one Timer Source Clock period for automatic reload of the}
Countdown Timer value ,n’.
4 _{To reset Interrupt signal ( INT ), Timer Flag “TF” has to be cleared by writing = “0”.}
5 _{When Countdown Timer is in automatic reload mode, one additional timer source clock has to be taken}
into account since it results in a Timer duration of ,n+1’ for subsequent timer periods.
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