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GENERAL DESCRIPTION

The RTS/RTM1760 is a complete dual redundant MIL-STD-1760 or MIL-STD-1553B Remote Terminal in a single small outline package. It is also capable of meeting the McAir response time requirements and the optional handling of modecode descriptor 31 as a normal subaddress. The mode of operation is selectable using two external pins. The RTS/RTM1760 contains two low-power monolithic transceivers capable of providing the output voltage required for MIL-STD-1760 (20V to 27V) together with a custom protocol chip and an optional 4K x 16 RAM for message storage. The custom transceiver chips are implemented in CMOS technology providing very low power consumption figures when not transmitting. The receiver sections of the transceivers fully meet the requirements of MIL-STD-1553B in terms of threshold, common mode rejection and bit error rate when used in conjunction with the custom protocol chip.The custom protocol chip contains dual redundant encoder/decoders, RT protocol logic, 32 word message buffers, DMA controller, arbitration logic and control registers. The internal RAM is used to separately store messages to all valid receive, transmit and broadcast subaddresses as well as modecode data. The complete terminal requires only a single +5V supply.In MIL-STD-1760 mode the RTS/RTM1760 provides selectable automatic checksum generation and validation together with header word/subaddress comparison on user selected messages. Other MIL-STD-1760 features include a latch on the RT address lines, checking to ensure that maximum message length is 30 words and generation of the AIRPRES* signal.In MIL-STD-1553B mode the special MIL-STD-1760 features are turned off and the unit functions as a standard Remote Terminal capable of performing all specified message formats. In both modes of operation the RTS/RTM1760 supports all 13 dual redundant modecodes. Illegalisation of any number of receive, transmit or broadcast subaddresses can be programmed using the 32 word Interface Control Block. This block can also be used to select modecode illegalisation and program interrupt generation on different subaddress or modecode combinations. It can also be used to select automatic checksum generation or validation if the terminal is operating in MIL-STD-1760 mode. With the addition of extemal circuitry (eg. a single PLD) any combination of subaddress, T/R bit, word count/modecode field can be declared illegal. The RTS/RTM 1760 can be easily interfaced to 8 and 16 bit processor architectures and in 8 bit mode all multiplexing is performed internally allowing 8 and 16 bit transfers to be mixed.In McAir mode the response time meets the required 7.0

µs

maximum. In addition subaddress 31 is allocated as a normal subaddress rather than a modecode. It should be noted that the databus drivers used in the RTS/RTM1760 conform to the requirements of MIL-STD-1553B and MIL-STD-1760 and not to those of McAir.

RECOMMENDED OPERATING CONDITIONS POWER SUPPLY CURRENTS

PARAMETERMINMAXUNIT Supply voltage (V
CCA , V
CCB , V
CCC , V
DC CCD )4.55.5V High level input voltage V
ih 2.2VLow level input voltage V
il 0.7VHigh level output voltage V
oh V
CCC VLow level output current I
ol 4mAOperating Case Temperature Range-55125Deg. C PARAMETERMINMAXUNIT I
CCA or I
CCB Transmit 25% duty cycle150250mATransmitter quiescent2060mAI

RT 1760 Package Options

CCC 550mAI
CCD 501000

For further information contact us at:

C-MAC MicroTechnology South Denes, Great Yarmouth, Tel: +44 (0) 1493 743 100Norfolk, NR30 3PX, UK Email: info@cmac.comJanuary 2008