73M2901/5V
Advanced Single
Chip Modem
4
PIN DESCRIPTIONS (continued) OSCILLATOR PIN DESCRIPTION
PIN NAME 32-PIN
44-PIN
TYPE DESCRIPTION
OSCIN 24 26 I Crystal input for internal oscillator, also input for external
source.
OSCOUT 23 25 O Crystal oscillator output.
DIGITAL INTERFACE PIN DESCRIPTION
PIN NAME 32-PIN
44-PIN
TYPE DESCRIPTION
RESET 13 9 I Resets 73M2901/5V
RXCLK 31 36 O Receive Data Synchronous Clock
RXD 30 35 O Serial output to DTE.
TXCLK 28 31 O Transmit Data Synchronous Clock
TXD 27 30 I Serial data input from DTE.
USR10 12 8 I/O This pin can optionally be configured as an active low detect
pin. This can be used to implement such functions as “parallel-
pick-up”, “line-in-use”, or “seize” detect.
USR11 11 7 I/O Programmable I/O port. This pin can ooptionnaly be used to
control an external switch for Caller ID decoding operations.
RTS (USR12) 10 6 I Request to Send
CTS (USR13) 9 5 O Clear to Send
DSR (USR14) 8 4 O Data Set Ready
DCD (USR15) 7 3 O Data Carrier Detect
RI (USR16) 4 43 O Ring Indicator
RELAY (USR17) 3 40 O Relay driver output