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2 D Meshes and 2 D Toroids

Other • 2-D meshes are one of the easiest topologies to visualize – nodes are connected in a “grid” fashion (see Figure). The simple layout also allows many problems to map easily to the structure of this network. 2-D Mesh and 2-D Toroid 2-D meshes have unequal node degree. The node degree...

Joint Architecture Standard Overview > Network Topologies > 2 D Meshes and 2 D Toroids

3 D Meshes and 3 D Toroids

Other • 3-D meshes and 3-D toroids are similar to 2-D meshes and toroids, except the 3-D mesh/toroid is expanded along the Z-axis to provide another dimensional layer of nodes. In the case of the 3-D toroid, the topmost nodes (along the new Z-axis) are connected to the bottommost nodes (see Figure)....

Joint Architecture Standard Overview > Network Topologies > 3 D Meshes and 3 D Toroids

Acknowledgement and Retransmit

Specification • The receiver shall send a positive acknowledgment (ACK) packet for each DATA packet received without error.

Communication Specification > SpaceWire > Protocols > JAS Reliable Data Delivery Protocol > Overall Functional Description > Acknowledgement and Retransmit

Acronyms

Other • Acronym Definition A/D Analog-to-Digital (as in A/D converter) ACK Acknowledge ADC Analog-to-Digital Converter API Application Program Interface APID Application Identifier APP Application CCC Cube-Connected Cycles CCITT From French: Comité Consultatif International Téléphonique et Télégraphique International Telegraph and Telephone Consultative Committee CC-NUMA Cache Coherent-Non-Uniform Memory Access CCSDS Consultative Committee for Space...

Joint Architecture Standard Overview > Acronyms

Addressing

Profile • SpaceWire supports three types of addressing: Path (Physical) Addressing, Logical Addressing, and Regional Addressing. JAS uses regional addressing because it provides the greatest flexibility to create scalable networks. Regional addressing uses a two-byte scheme where the first byte identifies the router and the second byte identifies the endpoint address connected...

Communication Profile > Interconnect Technologies > SpaceWire Interconnect > SpaceWire Transport > Addressing

Advantages of JAS

Other • A modern node-based architecture with reconfigurable node electronics and serial data links between nodes provides the core structure and flexibility needed to enable most of the design strategies. It offers a powerful, yet efficient, modular solution that can be scaled and configured to support payloads of virtually any size and...

Joint Architecture Standard Overview > JAS Rationale and Motivation > Advantages of JAS

Allocation of Service Types and Subtypes

Specification • The PUS provides a standard set of services that are targeted for communication between spacecraft and ground systems. Many of them may not be applicable to on-board communication between applications. However, nothing precludes their use in a JAS-based system. The PUS can be extended to add additional functionality to existing...

Communication Specification > JAS Packets > Packet Service Definitions > Allocation of Service Types and Subtypes

Analog Electronics

Profile • This instantiation of the Expansion Profile implements a 6U VPX board to include analog electronics and connectors to access incoming signals from external sensor modules. The analog electronics are connected to an RP node through the system backplane. The FPGA on the RP node filters and processes the incoming data...

Expansion Profile > Applications > Analog Electronics

Analog to Digital Converter and Multiplexer

Profile • SMAC ADC and Analog MUX The SMAC shall include an ADC to take analog measurements of board parameters (voltage, current, temperature). These values are returned to the system controller as SOH information. An analog MUX may be required so that multiple analog values can be read by the ADC. The...

System Monitoring and Communication Profile > Functional Description > Analog to Digital Converter and Multiplexer

Applications

Profile • Common instantiations of the CH profile include, but are not limited to: Host Vehicle Interface and Configuration Manager Mission Data Processing Non-Volatile Memory Storage Mass Memory Node The CH node can operate in several capacities, the most essential of which is the Host Vehicle Interface and Configuration Manager. However, several...

Command and Host Processor Profile > Applications

Applications

Profile • Instantiations of the Expansion Profile can improve the versatility of other node profiles by adding additional capability, connectivity, or capacity. Common instantiations of the Expansion Profile include, but are not limited to: Host vehicle interface Memory storage Rear transition module Analog electronics

Expansion Profile > Applications

Applications

Profile • Instantiations of this profile are intended to function as primary-to-secondary power converters, producing the secondary voltage rail(s) that are distributed to other nodes. The ‘Local POL Power Conversion’ section mentions one “or more secondary voltage rails” being produced by the PS node. One voltage rail (typically +5 or +12 V)...

Power Supply Profile > Applications

Backplane Connectors

Specification • JAS electrical design should utilize commercial connector standards when applicable. The VPX plug-in module to backplane connector is a Tyco Electronics MultiGig RT2 connector system which was chosen for its rugged mechanical performance and high-speed electrical performance, rated to 6.4 Gb/s and demonstrated to support data rates greater than 10...

Electrical Specification > Electrical Interconnects > VPX > Backplane Connectors