GPM Spacecraft Ethernet Study

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GPM Spacecraft EthernetStudy

• John Godfrey Code 561
• Rick Schnurr Code 560
• Mike Lin Code 561

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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.

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Proposed GPM Architecture
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Ethernet Spacecraft Network
Ethernet Space LAN
Network Interface Card
LVDS Physical Layer
Power Distribution Unit (PDU)
Guidance, Navigation and Control (GNC)
Ethernet Switch
NIC
NIC
Switch
Command and Data Handling
Communications Card (COM)
NIC
NIC
Media Converter
Building LAN (or commercial Ethernet test
equipment)
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Mil-Std-1553/SpaceWire vs Ethernet
Mil-Std-1553/SpaceWire 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
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Ethernet Network Interface Card (NIC)
Actel SX32 PCI Interface
UTMC LVDS Transceivers
Actel SX32 PHY
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
UTMC LVDS Transceivers
Actel SX32 PHY
12.5 MHz
2.5 MHz
LVDS Node 2
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Comm Card Ethernet Interface
Parallel, Serial, I/O
Actel SX72 I/O Interface /Router
UTMC LVDS Transceivers
Actel SX32 PHY
12.5 MHz
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
UTMC LVDS Transceivers
Actel SX32 PHY
12.5 MHz
2.5 MHz
LVDS Node 2
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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.

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Ethernet Switch (8 Port ESTO Funded)
MII
Actel SX72 FPGA Fabric, Arbitor, Lookup
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
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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.

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Media Converter
Programmable Logic
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
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GPM NIC Breadboard (ESTO Funded)
Xilinx Virtex FPGA
Actel FPGA
PCI Interface
Ethernet MAC
Back-End I/F Memory Controller
LVDS Trans- ceivers
LVDS
PHY
cPCI
PHY
Ethernet MAC
Memory
Additional Parts Osc, EEPROM, etc.
Memory
Test Points
Memory either inside or external
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SpaceLAN Breadboard Diagram
Xilinx XC2V4000
Actel SX72S
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
Oscillator, Reset, Power Regulators etc.
Ethernet Physical Layer
1 Ethernet Port
10/100 Ethernet Transceiver
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SpaceLAN Breadboard
Multiple use design Will be used as either an
Ethernet NIC or a SpaceWire NIC for this task
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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