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Command and Data Handling

Command and Data Handling. Li, Michael Jayaraman, Vijay Bhatia, Vishal Winkelman, Martin. Introduction. Command and Data Handling subsystem is responsible for computing and control of subsystem functions.

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Command and Data Handling

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  1. Command and Data Handling Li, Michael Jayaraman, Vijay Bhatia, Vishal Winkelman, Martin

  2. Introduction • Command and Data Handling subsystem is responsible for computing and control of subsystem functions. • The core of this subsystem is a single-board computer powered by the Intel PXA255 Processor. Colorado Space Grant Consortium

  3. Design Requirements • C&DH must not exceed 7 Watts. • Maximum ½ kg. • External watchdog timer. • External reset. • 3.8” x 3.6” x 4” minimum profile • Must run Linux • 32MB RAM minimum • 8MB FLASH minimum Colorado Space Grant Consortium

  4. Interfaces Colorado Space Grant Consortium

  5. Arcom Viper • PXA255 400Mhz CPU • SDRAM: 64M • FLASH: 16M • 256K Battery Backed SRAM • Real-Time Clock • Watchdog Timer • Interfaces: • 2 USB v1.1 • 5 Serial Ports • Compact Flash Drive Support • Ethernet: 10/100BaseT • JTAG • 8 GPIO • PC/104 Colorado Space Grant Consortium

  6. Power Consumption Colorado Space Grant Consortium

  7. Specifications (Viper overview) • Power Requirements: • 1.6W @ + 5V only supply (typical) • 200mW @ +5V (standby mode) • Operating Temperature: • -20°C to +70°C • -40°C to +85°C (extended) • Form Factor: PC104 Colorado Space Grant Consortium

  8. Design Options • MIP405 • RPXLITE • VIPER Colorado Space Grant Consortium

  9. OPTIONS CONSIDERED Option 1 : MIP405 • Integrated embedded IBM PowerPC processor • 375 DMIPS at 266MHz or PPC405GPr with 608 DMIPS at 400MHz • Power consumption Typically < 5.0 Watts • Ethernet, USB and 128MB SDRAM Pros • 128MB on-board soldered SDRAM (ECC support), up to 4MB on-board soldered Flash. • SRAM, EPROM, Flash and Disk-On-Chip modules can be added for keeping a redundant copy of the Flight Operating System as a back up in case of failure. Cons • Higher power consumption. • Doesn’t come with pre-loaded version of RedBoot Linux !! Colorado Space Grant Consortium

  10. OPTIONS CONSIDERED Option 2 : RPX Lite • Integrated single-board computer based on the Motorola MPC823 version. • Capable of providing the user with a bandwidth of up to 80MHz. • Mechanical specifications of the PC104 standard • 32, or 64 Mbytes SDRAM16 • 2, 4, 8, or 16 Mbytes Flash • 0, 32, 128, 512 Kbytes NVRAM/RTC • SCC2 - 10BaseT (RJ-45) Ethernet port Pros • The Dino team could get some help from the 3CS team as this has been previously used in the 3CS project. Cons • Processor speed – 80MHz. Much less compared to the Viper. • Cost Per Unit ~$900. Much more expensive compared to other SBCs. • Poor technical support. Colorado Space Grant Consortium

  11. Reasons For Design Decision • Ultra Low power consumption of 1.6Watts. • Has most number of Serial ports as compared to the other boards. • Provides 8 General Purpose I/O pins with expansion possibilities. • Meets all interface and design requirements. • Good processing speed of 400MHz. • Low Cost – Only $400!! • Lead Time of around 1-2 Weeks. • As the board is pretty new, it would be easily available in the market until Dec 2005. • Dr. Sam Siewert and his team of researchers from the ECE department (CU) are using the same Viper board in their research. He would be a great source of information regarding Viper incase the C&DH team needs his advice Colorado Space Grant Consortium

  12. Other Unexplored Options • EBC-C3 Winsystems SBC up to 700MHz via Eden processor. • SAT-520PLUS Winsystems SBC featuring 133MHz processor. Colorado Space Grant Consortium

  13. Testing Plans UART TEST – TX/RX verified on a terminal Ethernet controller test – try pinging an IP address on the same network and say one IP outside the network (proposed to be used when we run short of the serial ports esp. for debugging and loading code on to the board…) RAM test – try writing all 0s and all 1s and read them back. Try writing alternate 1s and 0s and try reading back and verifying the data Flash test – similar to the RAM test. Test with the actual viper board. test with a potentiometer which varies the voltage to the A/D converter. JTAG Interface can be used to troubleshoot system hangs Colorado Space Grant Consortium

  14. Testing Plans (cont.) • Test individual I/O pins. • Test USB – Probe bus and detect cameras • Test FPGA - Assert certain pins, test schematic. • Radiation Tolerance tests (industry supported?) Colorado Space Grant Consortium

  15. Budget Colorado Space Grant Consortium

  16. System Block Diagram Colorado Space Grant Consortium

  17. Temp. Sensor Thermal Interface Flight Computer Sensor select for temperature reading Digital Temp. readings select ADC Sensors in different parts of DINO MUX 10k +5V Temp. Sensor Colorado Space Grant Consortium

  18. Voltage proportional to temperature change Temperature-controlled Variable Resistor Temperature Sensors Colorado Space Grant Consortium

  19. Watchdog and Reset Decoder • Built-in watchdog on Viper • Reset decoder will be implemented in FPGA Colorado Space Grant Consortium

  20. Issues and Concerns • Radiation Shielding (How much, what kind…) • BSP Software Licensing • Testing Platform (Development Kit?) Colorado Space Grant Consortium

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