si2401 Silicon Laboratories, si2401 Datasheet - Page 70

• Manufacturer Part Number: si2401
• Description: V.22bis Isomodem With Integrated Global Daa
• Manufacturer: Silicon Laboratories

Si2401
70
Pin #
12
13
14
15
16
11
GPIO1/EOFR
GPIO3/ESC
GPIO4/INT/
GPIO2/CD
Pin Name
AOUT
GND
V
A
General Purpose Input/INT.
This pin can be either a GPIO pin (digital in, digital out) or the INT pin. Default is digital
in. When programmed as INT, this pin provides five functions. While the modem is
connected, it asserts if the carrier is lost, a wake-on ring (using the “ATZ” command)
event is detected, a loss of loop current event is detected, V.23 reversal is detected, or
if an intrusion event has been detected. The INT pin is sticky and stays asserted until
the host clears it by writing to the correct S register. (See register SE2[7:6].)
Ground.
Connects to the system digital ground.
Regulator Voltage Reference.
This pin connects to an external capacitor and serves as the reference for the internal
voltage regulator.
General Purpose Input/Escape.
This pin can be either a GPIO pin (digital in, digital out) or the ESC pin. Default is digi-
tal in. When programmed as ESC, a positive edge on this pin causes the modem to go
from online (connected) mode to the offline (command) mode.
General Purpose Input/CD.
This pin can be either a GPIO pin (digital in, digital out) or the CD pin. Default is digital
in. When programmed as CD, it is the active low carrier detect pin.
General Purpose Input/EOFR.
This pin can be either a GPIO pin (digital in, digital out) or the EOFR pin. Default is
digital in. This pin can also be programmed to function as the EOFR (end-of-frame
receive) signal for HDLC framing.
Rev. 1.0
Description