MA28139 Dynex Semiconductor, MA28139 Datasheet

MA28139

Manufacturer Part Number

MA28139

Description

Obdh Bus Terminal Databus

Manufacturer

Dynex Semiconductor

Datasheet

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Replaces January 2000 version, DS3592-6.0

Data Handling bus. Developed under ESA Contract, it

conforms to ESA OBDH, Digital Bus Interface and Internal

User Bus Standards.

modem which, on the bus side, provides the digital waveforms

necessary to operate the Litton Bus drivers, and receives the

outputs of the Litton bus detectors.

provides an input / output at Digital Bus Interface level. The

second function, internally coupled to the first, provides a

multiplexing / demultiplexing function of the DBI signals down

to Internal User Bus levels and vectored 16 bit serial register

read and write commands (see section 7.2 of ESA standard

TTC-B-01). In effect, the second function of the OBT provides

the core of an RTU.

two functions may be either coupled together (in RT mode) or

isolated (in CT mode). The device may hence be used as a

modem only, an RTU kernel only or as a combined modem

and RTU kernel. In RT mode, the Interrogation bus data

stream can be observed and the Response bus data from

associated devices, such as an MA28138 Remote Bus

Interface, can be combined with that from the RTU kernel

before being used by the modem circuits to modulate the

Response bus. Bi-directional access to the Block Transfer bus

is provided in either mode.

The OBT ASIC will interface any user to the ESA On Board

The OBT has 2 separate functions. The first is a 5 channel

The Interrogation and Response bus data streams of the

OBDH BUS

I R BT

R (RTU)

BT Rx

R Rx

BT Rx

I Rx

I (CTU)

On the user side, it

CLK DETECTOR,

Figure 1: Block Diagram

WATCHDOG

CONTROL

LOGIC

PINS

the OBT should be continuously clocked in order to output

timing to all users on the I-bus as dummy interrogations from

the CT. Commands and telemetry are normally sent on the I

and BT busses whilst responses and telemetry normally return

on the R and BT busses.

FEATURES

When used to interface a central terminal to the OBDH bus,

Radiation Hard

Low Power Consumption

Single CMOS-SOS ASIC Implementation

Latch-up Free

High SEU Immunity

Fully Compliant with ESA OBDH, IUB, DBI and RBI

Specification

Contains OBDH Bus Modem and RTU Kernel

Supports Bi-directional Data Transfer on Response and

Block Transfer Bus

CONFIGURATION PINS

KERNEL

RTU

OBDH Bus Terminal

DS3592-6.1 July 2002

MA28139

INTERNAL

USER

BUS

DIGITAL

BUS

INTERFACE

MA28139

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