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
