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GPM Spacecraft Ethernet Study
John Godfrey Code 561 Rick Schnurr Code 560 Mike Lin Code 561 October 10, 2002
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Network Interface Card (NIC)
Ethernet Components Network Interface Card (NIC) One dual port NIC required per box Ethernet Switch 12 port switch required for Primary Network 12 port Switch required for Secondary Network Media Converter Converts between flight physical hardware and standard ground Ethernet networks. October 10, 2002
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Proposed GPM Architecture
October 10, 2002
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Ethernet Spacecraft Network
Ethernet Space LAN Network Interface Card Power Distribution Unit (PDU) LVDS Physical Layer Guidance, Navigation and Control (GNC) Ethernet Switch NIC NIC Switch Command and Data Handling NIC NIC Communications Card (COM) Media Converter Building LAN (or commercial Ethernet test equipment) October 10, 2002
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Mil-Std-1553/SpaceWire vs Ethernet
Cost 1.8 M$ 2.0 M$ Power 50W 58W Mass 16 Kg 20 Kg Risk Very little development risk ESTO/SOMO SpaceLan activity has retired hardware development risk. Any unforeseen risk is mitigated by ability to fallback to 1553 approach GSE SpaceWire GSE is custom, 1553 GSE is relatively expensive Very low cost and risk October 10, 2002
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Ethernet Network Interface Card (NIC)
Actel SX32 PCI Interface Actel SX32 PHY UTMC LVDS Transceivers cPCI 12.5 MHz 2.5 MHz 25 MHz Actel SX72 MAC LVDS Node 1 Physical = 4B/5B, LVDS, Data Strobe Encoded 2 pairs xmit / 2 pairs rec. 12.5 MHz xmit rate Actel SX72 Memory Controller 33 MHz 33 MHz MAC 25 MHz Memory 4Mbit SRAM Actel SX32 PHY UTMC LVDS Transceivers 12.5 MHz 2.5 MHz LVDS Node 2 October 10, 2002
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Comm Card Ethernet Interface
Parallel, Serial, I/O Actel SX72 I/O Interface /Router 12.5 MHz Actel SX32 PHY UTMC LVDS Transceivers 2.5 MHz 33 MHz LVDS Node 1 Actel SX72 MAC Physical = 4B/5B, LVDS, Data Strobe Encoded 2 pairs xmit / 2 pairs rec. 12.5 MHz xmit rate Actel SX72 Memory Controller 33 MHz MAC 33 MHz 25 MHz Memory 4Mbit SRAM Actel SX32 PHY UTMC LVDS Transceivers 12.5 MHz 2.5 MHz LVDS Node 2 October 10, 2002
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12 Port Ethernet Switch Ethernet Switch will be implemented as a separate box. Switch will consist of five Actel FPGAs, SRAM and one LVDS driver/receiver pair per port. Switch is estimated to occupy a single 6U plus card, including both the switch and an independent power supply. October 10, 2002
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Ethernet Switch (8 Port ESTO Funded)
Actel SX72 FPGA Fabric, Arbitor, Lookup MII Actel SX72 FPGA UTMC LVDS Trans- ceivers LVDS Memory Lookup Table PHY PHY PHY PHY 4 ports Actel SX72 FPGA UTMC LVDS Trans- ceivers LVDS PHY PHY PHY PHY Actel SX72 FPGA FIFO Engine 4 ports Memory Frame Buffers Actel SX72 FPGA UTMC LVDS Trans- ceivers LVDS PHY PHY PHY PHY 4 ports GPM extension October 10, 2002
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Media Converter Media Converter will connect/bridge flight Ethernet to any ground Ethernet network. Flight physical layer is LVDS and must be converted to standard Ethernet interface. Media converter enables the use of standard ethernet routers, network cards, and bus analyzers for testing and debugging the spacecraft network. October 10, 2002
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Media Converter Programmable Logic Glue Logic MII MII RJ-45 DB-9
10/100 Data Strobe LVDS 10/100 BASE-TX Commercial 10/100BASE-TX Transceiver Glue Logic NASA/GSFC Physical Layer 10/100 Data Strobe LVDS (Verilog) MII MII RJ-45 DB-9 MII = Medium-Independent Interface October 10, 2002
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GPM NIC Breadboard (ESTO Funded)
Actel FPGA Xilinx Virtex FPGA PCI Interface Back-End I/F & Memory Controller Ethernet MAC PHY LVDS Trans- ceivers LVDS cPCI Ethernet MAC PHY Memory* Additional Parts Osc, EEPROM, etc. Memory* Test Points *Memory either inside or external October 10, 2002
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SpaceLAN Breadboard Diagram
Actel SX72S Xilinx XC2V4000 PCI Interface & Flash Memory Control 4 Million Gates LVDS Transceivers 108 LVDS I/O Lines Standard 32 bit / 33 MHz Compact PCI Interface Memory 2,160,000 bits RAM Flash Memory 8M x 8 18 LampsTotal 3 color Status lamps Memory SRAM 256K x 32 Memory SRAM 256K x 32 RS-232 Transceivers RS-232 ports 96 Test Points Oscillator, Reset, Power Regulators etc. Ethernet Physical Layer 1 Ethernet Port 10/100 Ethernet Transceiver October 10, 2002
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SpaceLAN Breadboard Multiple use design: Will be used as either an Ethernet NIC or a SpaceWire NIC for this task October 10, 2002
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Current SpaceLAN Status
Three test set-ups built (four total) 19 inch, 8 slot Compact PCI racks Motorola MCP750 processors Seven Blank boards procured Parts to populate 5 boards also procured First breadboard has been fabricated (March 21) and is now in testing Four more breadboards to follow in the coming weeks GPM is funding this continuing effort Ethernet HDL code is complete In test with first breadboard SpaceWire HDL code is complete, but not implementation simulated Awaiting hardware for test October 10, 2002
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