Rev. 0.8 12/11
Copyright © 2011 by Silicon Laboratories
AN332
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1. Introduction
This document provides an overview of the programming requirements for the Si4704/05/06/07/1x/2x/3x/4x/84/85
FM transmitter/AM/FM/SW/LW/WB receiver. The hardware control interface and software commands are detailed
along with several examples of the required steps to configure the device for various modes of operation.
2. Overview
This family of products is programmed using commands and responses. To perform an action, the system
controller writes a command byte and associated arguments, causing the device to execute the given command.
The device will, in turn, provide a response depending on the type of command that was sent. Section "4.
Commands and Responses" on page 6 and section "5. Commands and Properties" on page 7 describe the
procedures for using commands and responses and provide complete lists of commands, properties, and
responses.
The device has a slave control interface that allows the system controller to send commands to and receive
responses from the device using one of three serial protocols (or bus modes): 2-wire mode (I
2
C and SMBUS
compatible), 3-wire mode, or SPI mode.
Section "6. Control Interface" on page 224 describes the control interface in detail.
Section "7. Powerup" on page 232 describes options for the sequencing of VDD and VIO power supplies, selection
of the desired bus mode, provision of the reference clock, RCLK, and sending of the POWER_UP command.
Section "8. Powerdown" on page 239 describes sending the POWER_DOWN command and removing VDD and
VIO power supplies as necessary.
Section "9. Digital Audio Interface" on page 240 describes the digital audio format supported and how to operate
the device in digital mode.
Section "10. Timing" on page 243 describes the CTS (Clear to Send) timing indicating when the command has
been accepted and in most cases completed execution, and the STC (Seek/Tune Complete) timing indicating
when the Seek/Tune commands have completed execution.
Section "11. FM Transmitter" on page 249
describes the audio dynamic range control, limiter, pre-emphasis,
recommendations for maximizing audio volume for the FM transmitter.
Section "12. Programming Examples" on page 253 provides flowcharts and step-by-step procedures for
programming the device.