MX809J データシートの表示（PDF） - MX-COM Inc

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MX809J

1200bps MSK Modem

MX-COM Inc  

DATA BULLETIN

MX809 1200bps MSK Modem

PRELIMINARY INFORMATION

Features

 Half-Duplex 1200bps MSK Modem

operating under C-BUS control

 Software Selectable Checksum

Generation and Error Checking in

accordance with MPT1327

 Low Power Operation

 Member of DBS800 Family (C-BUS

Compatible)

RECOVERED

CLOCK

CHECKSUM

GEN/CHECK

BYTE COUNTER

RX IN

MSK

RECEIVER

RECOVERED

CLOCK

DATA REGISTER 1

DATA REGISTER 2

XTAL/

CLOCK

XTAL

CLOCK

GENERATOR

RX SYNC

DETECT

SYNC/SYNC

DETECT

RX SYNC

DETECT

RX FREEFORMAT

RX DATA BUFFER

TX DATA BUFFER

CS

REPLY

DATA

SERIAL

CLOCK

COMMAND

DATA

C-BUS

INTERFACE

AND

CONTROL

LOGIC

WAKE

INTERRUPT

ENABLE

RX DATA

READY

8-BIT PARALLEL BUS

ADDRESS

DECODER

ADDRESS

SELECT

TX DATA

READY

SYNC PROGRAM

LOW - HIGH

TX IDLE

RX SYNC

DETECT

RX SYNC

DETECT

CONTROL

REGISTER

STATUS

REGISTER

VDD

MSK

TRANSMITTER

TX OUT

VBIAS

AMP IN

_

VBIAS

+

AMP OUT

UNCOMMITTED

AMPLIFIER

VSS

INTERRUPT

GENERATOR

IRQ

The MX809 is an intelligent, half-duplex 1200-baud MSK Modem, which operates under C-BUS control. This

modem provides software selectable checksum generation and error checking in accordance with MPT1327.

In TX Mode the MX809 will:

1. a) Accept from the host and transmit 8-bit bytes of data as instructed (preamble, sync, address, and data), or

b) Internally calculate and inset a 2 byte checksum based on the preceding 6 bytes f data, or

c) Disable the internal checksum generator and continuously transmit the data supplied.

2.

Transmit 1 hang-bit and go to TX idle when all loaded data bytes have been transmitted.

In RX Mode the MX809 will:

1.

Detect and carry out bit synchronization within 16 bits.

2. a) Search and detect the user-programmed Sync (or its opposite logic sense) Word and carry out frame

synchronization. Data will then be output in 8-bit bytes via the RX Data Buffer.

b) Use the received checksum to calculate the presence of any errors, setting the Status Register accordingly.

3.

Make the incoming data directly available via the RX Data Buffer (RX Freeformat), overriding the synchronization

requirements.

RX input timing is achieved by recovering an RX clock from the incoming data stream. Output tones are

timed to the internally generated TX clock. Filter, register clocks, and transmit MSK tone frequencies are

derived internally from the external Xtal or clock pulse input.

A 4.032MHz Xtal or clock input is required for compliance with the MPT1327 Signaling Specification. Note:

All information contained in this data bulletin is specified using a 4.032MHz Xtal, 1200bps baud rate, with

Mark and Space frequencies of 1200Hz and 1800Hz. The MX809 has a non-committed amplifier on-chip for

general applications in the DBS 800 series.

The MX809 may be used with a 5.0V power supply and is available in the following packages:

24-pin PLCC (MX809LH), and 24-pin CERDIP (MX809J).

1998 MX-COM, Inc.

www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054

Doc. # 20480036.004

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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