RV-3029 Datasheet, PDF (43/67 Pages) MICORO CRYSTAL SWITZERLAND – DTCXO Temperature Compensated Real Time Clock

Micro Crystal
DTCXO Temperature Compensated Real Time Clock / Calendar Module
RV-3029
5.3.3.TESTING THE TIME ACCURACY USING INTERRUPT OUTPUT 1 Hz
The internal Countdown Timer can be used to generate a 1 Hz test signal at the INT output. However, this
procedure is more complicated than using CLKOUT, therefore the following instructions shall be read carefully to
avoid mistakes.
Enable temperature compensation:
• Select scanning interval 1 s:
• Enable thermometer:
set “ThP” = “0” (bit 0 register EEPROM Control)
set “ThE” = “1” (bit 1 register EEPROM Control)
Set appropriate test condition using Countdown Timer & 1 Hz INT Output:
• Disable Timer:
set “TE” = “0” (bit 1 register Control_1)
• Disable Timer Auto-Reload Mode: set “TAR” = “0” (bit 2 register Control_1)
Timer & Timer Auto Reload Mode needs to be disabled to allow changes in settings of the Timer Source Clock and
Countdown Timer value.
• Set Timer Source Clock = 8 Hz:
set “TD0” = “1“& “TD1” = “0” (bit 5&6 register Control_1)
• Set Countdown Timer Value n = 7: set register “Timer Low” = 07h (bit 0-7 register Timer Low)
set register “Timer High” = 00h (bit 0-7 register Timer High)
• Enable Timer Interrupt:
set “TIE” = “1” (bit 1 register Control_INT)
• Set Timer in Auto-Reload Mode: set “TAR” = “1” (bit 2 register Control_1)
• Enable Timer:
set “TE” = “1” (bit 1 register Control_1)
Prepare MCU Software Driver to clear INT signal:
• MCU clears INT signal:
Measuring equipment and setup:
clear INT by setting “TF” = “0” (bit 1 register Control_INT Flag)
• Use appropriate frequency counter: for example Agilent A53132A Universal Counter
• Gate time:
set gate time to 32 seconds (one complete compensation cycle)
• Trigger to negative slope:
set trigger to falling edge (negative slope)
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