RCH
INSTALLATION AND MAINTENANCE MANUAL model TOUCH ME
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9.11 QUARTZ OSCILLATING CIRCUITS
9.11.1 RTC CIRCUIT (time / date)
The PCF 8553 (X3) RTC circuit has time / date functions. It makes use of an external
quartz oscillating circuit (XT2) with 32,768kHz frequency for clock scanning. The circuit is
fed by the VB voltage, and has serial communication with the microprocessor (x1)
9.11.2 MICROPROCESSOR U17 CLOCK CIRCUIT
The terminals XIN – VSS1 - XOUT are connected to the quartz oscillating circuit XT1 (16
MHz) that scans the microprocessor work frequency.