MA28139 Datasheet, PDF (1/34 Pages) Dynex Semiconductor – OBDH Bus Terminal

Replaces June 1999 version, DS3592-5.0
MA^M2^A8²1⁸3¹³9⁹
OBDH Bus Terminal
DS3592-6.0 January 2000
The OBT ASIC will interface any user to the ESA On Board
Data Handling bus. Developed under ESA Contract, it
conforms to ESA OBDH, Digital Bus Interface and Internal
User Bus Standards.
The OBT has 2 separate functions. The first is a 5 channel
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. On the user side, it
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.
The Interrogation and Response bus data streams of the
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.
When used to interface a central terminal to the OBDH bus,
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
s Radiation Hard
s Low Power Consumption
s Single CMOS-SOS ASIC Implementation
s Latch-up Free
s High SEU Immunity
s Fully Compliant with ESA OBDH, IUB, DBI and RBI
Specification
s Contains OBDH Bus Modem and RTU Kernel
s Supports Bi-directional Data Transfer on Response and
Block Transfer Bus
OBDH BUS
I R BT
I Rx
R Rx
I
R
(CTU)
(RTU)
Tx
BT Rx
BT Rx
CONFIGURATION PINS
CLK DETECTOR,
WATCHDOG
RTU
KERNEL
CONTROL
LOGIC
INTERNAL
USER
BUS
DIGITAL
BUS
INTERFACE
CONTROL
PINS
Figure 1: Block Diagram
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