SI2457-D-FS Silicon Laboratories Inc, SI2457-D-FS Datasheet - Page 17

• Manufacturer Part Number: SI2457-D-FS
• Description: IC ISOMODEM SYSTEM-SIDE 16SOIC
• Manufacturer: Silicon Laboratories Inc

Specifications of SI2457-D-FS

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4. Functional Description
The Si2457/34/15/04 ISOmodem
embedded modem chipset with integrated direct access
arrangement (DAA) that provides a programmable line
interface to meet global telephone line requirements.
Available in two small packages, this solution includes a
DSP data pump, modem controller, on-chip RAM and
ROM, codec, DAA, analog output, and 27 MHz clock
input.
The Si2457/34/15/04 accepts standard modem AT
commands and provides connect rates up to 56/33.6/
14.4/2.4 kbps full-duplex over the Public Switched
Telephone Network (PSTN). The Si2457/34/15/04
features a complete set of modem protocols including all
ITU-T standard formats up to V.90.
To provide the most flexibility, the Si2457/34/15/04
ISOmodem system-side device is offered in either a 24-
pin TSSOP or a 16-pin SOIC package. The 16-pin
version
ISOmodem and is recommended for most applications.
The 16-pin version does not support the parallel,
EEPROM or voice codec interface. If these features are
required, customers should use the 24-pin version.
The ISOmodem provides numerous additional features
for embedded modem applications. The modem includes
full type I and type II caller ID detection and decoding for
global standards. Call progress monitoring is supported
through standard result codes. The modem is also
programmable to meet global settings. Because the
Si2457/34/15/04 ISOmodem integrates the DAA, analog
features, such as parallel phone detect, overcurrent
detection, and global PTT compliance with a single
design, are included.
CLKOUT
EECLK
RESET
D0-D7
EESD
EECS
MISO
MOSI
SCLK
RXD
DCD
TXD
CTS
RTS
ESC
WR
CS
RD
INT
A0
SS
RI
Figure 8. Functional Block Diagram
is
EEPROM
Interface
Interface
Interface
Interface
Parallel
UART
footprint-compatible
SPI
XTI
Clocking
PLL
XTO
Program Bus
Data Bus
ROM
RAM
Interface
®
with
DAA
is a complete
the
C1
C2
AOUT
Si2401
To Phone
Line
Rev. 1.3
This device is ideal for embedded modem applications
due to its small board space, low power consumption,
and global compliance. The Si2457/34/15/04 solution
includes a silicon DAA using Silicon Laboratories’
proprietary third-generation DAA technology. This highly-
integrated DAA can be programmed to meet worldwide
PTT specifications for ac termination, dc termination,
ringer impedance, and ringer threshold. In addition, the
Si2457/34/15/04 has been designed to meet the most
stringent worldwide requirements for out-of-band energy,
billing-tone immunity, surge immunity, and safety
requirements.
The Si2457/34/15/04 allows for rapid integration into
existing modem applications by providing a serial
interface that can directly communicate to either a
microcontroller via a UART interface or a PC via an RS-
232 port. This interface allows for PC evaluation of the
modem
commands using standard terminal software.
4.1. Host Interface
The Si2457/34/15/04 interfaces to the host processor
through either an asynchronous serial interface, a
synchronous Serial Peripheral Interface (SPI), or a
parallel interface.
communication. Selection of either SPI or parallel
interface is done on power-up with reset strapping.
Please refer to “AN93: ISOmodem
Designer's Guide” for details.
4.1.1. Asynchronous Serial Interface
The Si2457/34/15/04 supports asynchronous serial
communication with data terminal equipment (DTE) at
rates up to 307.2 kbps with the standard serial UART
format. Upon powerup, the UART baud rate is
automatically detected using the autobaud feature.
4.1.2. Serial Peripheral Interface (SPI)
The serial peripheral interface (SPI) provides a flexible,
full-duplex synchronous serial bus for host processor
and Si2457/34/15/04 ISOmodem communication. When
the Si2457/34/15/04 is powered up with SPI mode
enabled the modem becomes an SPI slave, and the
pins are configured to SS (slave select input, active
low), MOSI (serial data input to modem), MISO (serial
data output from modem) and SCLK (serial data clock
input).
address byte and a data byte.
4.1.3. Parallel Interface (24-Pin Version Only)
The Si2457/34/15/04 can also communicate via a
parallel interface when using the 24-pin version. The
parallel interface is an 8-bit data bus with a single bit
address to memory mapped registers.
Each SPI operation consists of a control-and-
immediately
Si2457/34/15/04
The default is asynchronous serial
upon
powerup
®
Chipset Family
via
the
AT
17