CMX644A Ver la hoja de datos (PDF) - MX-COM Inc
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CMX644A Datasheet PDF : 31 Pages
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Bell 212A / V.22 Modem with Call Progress and DTMF
4
CMX644A Preliminary Information
2 Signal List
CMX644A
D2/D5/P4
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20, 21, 22
Signal
Name
XTAL
XTAL/CLOCK
Type
output
input
SERIAL CLOCK
input
COMMAND DATA
input
REPLY DATA
tri-state
CS
input
IRQ
output
TX
TX+
TXIN-
TX-
VSS
VBIAS
RLYDRV
RX+
RX-
RXAMPOUT
RT
RD
-
output
output
input
output
power
output
output
input
input
output
bi-directional
N/C
Description
The inverted output of the on-chip oscillator.
The input to the on-chip oscillator, for external Xtal circuit
or clock.
The ‘C-BUS’ serial clock input. This clock, produced by
the µController, is used for the transfer timing of
commands to and from the device.
The ‘C-BUS’ serial data input from the µController. Data
is loaded into this device in 8-bit bytes, MSB (B7) first,
and LSB (B0) last, synchronized to the SERIAL CLOCK.
The ‘C-BUS’ serial data output to the µController. The
transmission of REPLY DATA bytes is synchronized to
the SERIAL CLOCK under control of the CS input. This
3-state output is held at high impedance when not
sending data to the µController.
Chip Select. The ‘C-BUS’ data loading control function:
this input is provided by the µController. Data transfer
sequences are initiated, completed or aborted by the CS
signal.
This output indicates an interrupt condition to the
µController by going to a logic ‘0’. This is a ‘wire-ORable’
output, enabling the connection of up to 8 peripherals to 1
interrupt port on the µController. This pin has a low
impedance pull-down to logic ‘0’ when active and a high
impedance when inactive. An external pull-up resistor is
required.
The output of the transmit gain control.
The output of the line driver amplifier.
The inverting input to the line driver amplifier.
The inverted output of the line driving amplifier. Pins TX+
and TX- provide symmetrical outputs for use with a
balanced load to give sufficient Tx line signal levels even
at low VDD.
The negative supply rail (ground).
A bias line for the internally circuitry, held at VDD/2. This
pin must be decoupled by a capacitor mounted close to
the device pins.
An open-drain output for controlling a relay.
The non-inverting input of the receive op-amp.
The inverting input of the receive op-amp.
The output of the receive op-amp.
Open-drain output and Schmitt trigger input forming part
of the Ring or Line Polarity Reversal detector. An
external resistor to VDD and a capacitor to VSS should be
connected to RT to filter and extend the RD input signal.
Input to the Ring or Line Polarity Reversal Detector.
No connections should be made to these pins.
2000 MX-COM, Inc.
www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054
Doc. # 20480197.006
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.
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