A report describes a prototype system interface assembly (SIA) that performs the functions of a compact, radiation-hard application-specific integrated circuit (ASIC) to be built subsequently. The SIA ASIC would be installed in a spacecraft, where it would function as a peripheralcomponent interface (PCI) with (a) four scientific instruments that generate highspeed serial data streams and (b) either of two spacecraft telecommunication systems — the Small Deep Space Transponder (SDST) or the Space Transponding Modem (STM). Once configured, the serial uplink and downlink channels would conform to the SDST serial interface protocol or the STM modified serial peripheral interface protocol. In the SDST configuration, the downlink could be further configured for Reed-Solomon coding, for turbo coding, for bypass mode, and/or to enable a pseudo-randomizer. The SIA ASIC would operate in conjunction with a bus controller/remote terminal/monitor ASIC (United Technologies BCRTM or equivalent) to provide the control and status interfaces to the telecommunication systems and/or other systems that conform to MIL-STD-1553 devices. The ASIC would control, and would serve as an interface to, memory circuitry configurable by the user as external first-in/first-out buffers for each of the telecommunication and instrument interfaces.
This work was done by Anwar Akhtar, Martin Le, John Gilbert, Alfred Khashaki, Carl Steiner, Donald Johnson, Dwight Geer, Julianne Romero, Keizo Ishikawa, Kenneth Crabtree, and Leonard Day of Caltech for NASA’s Jet Propulsion Laboratory. To obtain a copy of the report, “PCI Bridge to Telecom and Four Instrument Interfaces,” access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Electronic Components and Systems category. NPO-30278
This Brief includes a Technical Support Package (TSP).
PCI Bridge to Instruments and Telecommunication System
(reference NPO-30278) is currently available for download from the TSP library.
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Overview
The document presents a technical support package detailing the development of a System Interface Assembly (SIA) designed for use in spacecraft, specifically for NASA's Jet Propulsion Laboratory (JPL). The SIA is a prototype that functions as a compact, radiation-hard application-specific integrated circuit (ASIC) intended to interface with various scientific instruments and telecommunication systems.
The SIA ASIC is engineered to operate within a CompactPCI 3U card form factor, addressing the need for a robust telecommunications interface in the context of the X2000 Project, which aims to advance avionics technology for JPL flight projects. The architecture of the project was modified late in its development, necessitating the integration of new telecom and instrument interfaces that could accommodate two different telecommunication systems: the Small Deep Space Transponder (SDST) and the Space Transponding Modem (STM).
Key features of the SIA ASIC include its ability to provide PCI bridge functionality, enabling simultaneous communication with four high-speed serial instruments and the selected telecommunication system. The ASIC supports various configurations for uplink and downlink channels, adhering to the SDST serial interface protocol or the STM modified Serial Peripheral Interface (SPI) protocol. In SDST mode, the downlink can be further configured for advanced coding techniques such as Reed-Solomon and Turbo coding, as well as bypass mode and pseudo-randomization.
The SIA ASIC also interfaces with a bus controller/remote terminal/monitor ASIC (specifically the United Technologies BCRTM or equivalent) to manage control and status interfaces for telecommunication hardware and other MIL-STD-1553 devices. Additionally, it controls external memory that can be configured as first-in/first-out (FIFO) buffers for the various interfaces, enhancing data handling capabilities.
The development team, comprising experts from Caltech and JPL, has focused on ensuring that the SIA ASIC meets the unique high radiation environmental requirements of space missions. This innovative solution not only addresses the immediate needs of the X2000 Project but also sets a precedent for future spacecraft communication systems, emphasizing the importance of compact, reliable, and rad-hard technology in the exploration of space.
