Mobile Intel Pentium 4 Processor - M and Intel 845MP/MZ Chipset Platform Design Guide

Mobile Intel

Pentium

4 Processor-M and Intel

845MP/845MZ Chipset Platform

Design Guide 117

RTCX1 signal is amplified to drive internal logic as well as generate a free running full swing clock

output for system use. This output ball of the ICHn is called SUSCLK. This is illustrated in Figure 59.

Figure 59. RTCX1 and SUSCLK Relationship in ICH3-M

ICH3

Internal

Oscillator

RTCX1

SUSCLK

Low-Swing 32.768kHz

Sine Wave Source

Full-Swing 32.768kHz

Output Signal

For further information on the RTC, please consult Application Note AP-728

ICH/ICH2/ICH2M/ICH3S/ICH3M Real Time Clock (RTC) Accuracy and Considerations Under Test

Conditions

This section will present the recommended hookup for the RTC circuit for the ICH3-M.

9.9.1. RTC Crystal

The ICH3-M RTC module requires an external oscillating source of 32.768 kHz connected on the

RTCX1 and RTCX2 balls. The following figure documents the external circuitry that comprises the

oscillator of the ICH3-M RTC.