User`s manual

Configuring the Crystal Oscillator
CS485xx Hardware User’s Manual
DS734UM7 Copyright 2008 Cirrus Logic, Inc. 7-2
Figure 7-1. Crystal Oscillator Schematic
7.2 Configuring the Crystal Oscillator
After code download or soft reset, and before kickstarting the application, the host has the option of
changing the default hardware configuration. (Please see AN298, “CS485xx Firmware User’s Manual” for
more information on kickstarting). In general, the hardware configuration can only be changed immediately
after download or after soft reset.
Hardware configuration messages are used to configure the XTAL_OUT divider.
7.2.1 Crystal Oscillator Hardware Configuration Messages
Table 7-2 shows the command for configuring the XTAL_OUT pin for Divide-by-2 operation.
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Table 7-2. XTAL_OUT Configuration
Description Hex Message
XTAL_OUT Divide-by-2
0x81400042
0x00000800
1 Meg
C1 C1
X1
XTI
XTO
XTAL_OUT
To System
CS485xx