Texas Instruments OMAP5912 Reference Manual page 29

2.2 OMAP5912 Module Descriptions
2.2.1 Clock and Reset Generation
32-kHz Oscillator
12-MHz Oscillator
Ultralow-Power Device (ULPD)
OMAP5912 Clock and Reset Architecture
SPRU748A
The 32-kHz oscillator uses a 32-kHz external quartz. It can be used to
generate the 32-kHz clock on the chip. It can be disabled when the 32-kHz is
an external source provided by an external clock.
This oscillator is to be used with a 12-MHz or 13-MHz external quartz.
The 12- or 13-MHz oscillator allows the generation of the 48 MHz the USB
requires. The APLL located in the ULPD provides the x4 factor. The 12- or
13-MHz clock is used as the input clock of the ULPD. The 12- or 13-MHz
oscillator is on during awake and big sleep modes. It is off during deep sleep
mode. The wake-upsequence is handled from the power management
module.
The ULPD generates and manages clocks and reset signals to OMAP and to
some peripherals. It controls chip-level power-down modes and handles
chip-level wake-up events.
The ULPD can handle the high-frequency oscillator on/off sequences, when
used, and provides the resets to OMAP. It also allows configuration of the clock
sources of the OMAP5912 device and management of the APLL interface.
The global clock distribution and the reset distribution scheme are described
in Chapter 5.
OMAP5912 Description
Introduction 29