Specifications

Si2457/34/15/04
Rev. 1.3 45
7. Pin Descriptions: Si2457/34/15/04 (16-Pin Option)
Pin # Pin Name Description
1CLKIN/XTALIXTALI—Crystal Oscillator Pin.
Provides support for parallel resonant AT cut crystals. A 4.9152 MHz or 32.768 kHz crystal
or a 32.768 kHz or 4.9152 or 27 MHz clock on XTALI is required.
2XTALOXTALO—Crystal Oscillator Pin.
Serves as the output of the crystal amplifier.
3RI
Ring Indicator.
The RI
on (active low) indicates the presence of an ON segment of a ring signal on the tele-
phone line.
4V
D
Supply Voltage.
Provides the 3.3 V supply voltage to the Si2457/34/15/04.
5 MISO/RXD Master In Slave Out/Receive Data.
Serial data output from modem in SPI mode.
Data output to DTE RXD pin in UART mode.
6MOSI/TXDMaster Out Slave In/Transmit Data.
Serial data input to modem in SPI mode.
Data input from DTE TXD pin in UART mode.
7SCLK/CTS
Serial Data Clock/Clear to Send.
Signals that the Si2457/34/15/04 is ready to receive more digital data on the TXD pin.
Serial data clock input in SPI mode.
8 RESET
Reset Input.
An active low input that is used to reset all control registers to a defined, initialized
state.
9C2AIsolation Capacitor 2A.
Connects to one side of the isolation capacitor C2.
10 C1A Isolation Capacitor 1A.
Connects to one side of the isolation capacitor C1.
11 INT
Interrupt Output.
Active low interrupt output.
CLKIN/XTALI
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
XTALO
RI
V
D
MISO/RXD
MOSI/TXD
SCLK/CTS
RESET
C2A
C1A
INT
GND
V
A
ESC
DCD
SS/RTS
1
Si2457/34/15/04
(16-Pin Option)