Rtc Design Guidelines; Real Time Clock General Introduction; Description; Real Time Clock Signal Descriptions - Intel Quark SoC X1000 Design Manual

RTC Design Guidelines—Intel
12.0

RTC Design Guidelines

12.1

Real Time Clock General Introduction

12.1.1

Description

®
the Intel
battery-backed SRAM. The internal RTC module provides two key functions: keeping
date and time and storing system data in its RAM when the system is powered down.
SoC RTC module defaults to using an internal clock source alternatively an external
oscillating source of 32.768 kHz connected on the RTCX1 and RTCX2 balls.
shows the external circuitry that comprises the oscillator of SoC RTC.
The SoC uses a crystal circuit to generate a low-swing 32 kHz input sine wave. This
input is amplified and driven back to the crystal circuit via the RTCX2 signal. Internal to
the SoC, the RTCX1 signal is amplified to drive internal logic as well as generate a free
running full swing clock output from the RTC for internal system use. This is illustrated
in Figure
.
Figure 41.

RTCX1 and RTCX2 Relationship in SoC

Low-Swing 32.768kHz
Sine Wave Source
12.2

Real Time Clock Signal Descriptions

12.2.1

Signal Groups

Table 45.

RTC Signals

Section
Section 12.3.2
Section 12.3.2
Section 12.5
June 2014
Order Number: 330258-002US
®
Quark™ SoC X1000
Quark™ SoC X1000 contains a real time clock (RTC) with 256 bytes of
41.
Group
Crystal Input 1
Crystal Input 2
Reset
SoC
RTCX1
Internal
Oscillator
Full-Swing 32.768kHz
Output Signal
SUSCLK
Signals
RTCX1
RTCX2
RTCRSTB (I_1PAD)
Figure 42
Description
Crystal Input 1
Crystal Input 2
RTC Reset
®
Intel Quark™ SoC X1000
PDG
85