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2000-10-11 RYP-KS A Study On Different 32 And 16-bit Processors For Low-Earth Orbit Space Applications Krister Sundström Master’s Project.

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Presentation on theme: "2000-10-11 RYP-KS A Study On Different 32 And 16-bit Processors For Low-Earth Orbit Space Applications Krister Sundström Master’s Project."— Presentation transcript:

1 2000-10-11 RYP-KS A Study On Different 32 And 16-bit Processors For Low-Earth Orbit Space Applications Krister Sundström Master’s Project

2 2000-10-11 RYP-KS Background Data  Low-Earth Orbit: 400 - 600 km altitude  Short Lifetime: ~ 3 years  Small-Satellite Constellation:~ 60 kg/satellite >100 satellites

3 2000-10-11 RYP-KS Background Information  On-Board Computer Systems (OBC)  Real-Time Systems (RTS)  Single Event Effects (SEE)  Parasitic Silicon Controlled Rectifier  Interrupt Phillosophy

4 2000-10-11 RYP-KS Data Handling System  Central Part of The Satellite Mission Software Subsystem Master Shared Processing Power

5 2000-10-11 RYP-KS  Availability  Error Tolerance And Recovery Error Detection And Correction (EDAC) Watchdog Study Topics

6 2000-10-11 RYP-KS  Peripheral Support  Serial & parallel ports / Bus controllers  Memory types  Multitask Support  Real-time system  Context switching  Processor Architectures Study Topics

7 2000-10-11 RYP-KS What Is A Real-Time System?  Correct functionality, at the right time Soft RTS  Instrument Data Collection  Missed Soft Deadline   System still functional  Some degradations Hard RTS  Attitude & Orbit Control System (AOCS)  Missed Hard Deadline   Catastrophe may follow

8 2000-10-11 RYP-KS Single Event Effects (cont.) A Simple Memory Cell Model

9 2000-10-11 RYP-KS Single Event Effects (cont.)  Spread Out Data Bits  Less risk for multiple bit error

10 2000-10-11 RYP-KS Parasitic SCR  Can Cause Permanent Damage Single Event Latch-up Single Event Burn-out (SEB)  Current Limiter  Silicon On Insulator (SOI) SCR - Silicon Controlled Rectifier

11 2000-10-11 RYP-KS EDAC (cont.) Checkbit Generator =

12 2000-10-11 RYP-KS Interrupts  Masked  Threshold

13 2000-10-11 RYP-KS Different Processors  RH Thor (32)Saab Ericsson  ERC32 (32)Temics  Leon (32)ESA  HS-RTX2010 RH (16)Harris

14 2000-10-11 RYP-KS RH Thor  32-bit, 4-Stage Pipelined RISC Processor  2 Giby Address Space 1 Giby = 2 30 bytes

15 2000-10-11 RYP-KS RH Thor (cont.)  Hardware Support For Task Switching  Exception  Resume  SOI – Silicon On Insulator

16 2000-10-11 RYP-KS ERC32  Fully SPARC v7 Compatible  3 Main Blocks; IU, MC, FPU IU FPU MC DMA I/O

17 2000-10-11 RYP-KS ERC32  32 Miby Address Space  Multitask Support – Windows Register File 1 Miby = 2 20 bytes

18 2000-10-11 RYP-KS Leon  Open-sourced – Free VHDL Code  Small Design – 30 kGates (without FPU)  100% ERC32 Compatible  Fully SPARC v8 Compatible

19 2000-10-11 RYP-KS Leon (cont.)  Many On-Chip Peripheral Interfaces  1 Giby Address Space  Multitask Support

20 2000-10-11 RYP-KS HS-RTX2010 RH  Small, Well Used 16-bit Processor  High Radiation Tolerant (>300 kRAD)  1 Miby Address Space

21 2000-10-11 RYP-KS Why Leon?  Open-sourced architecture  Free VHDL-code  Optimisation  On-chip add-on possibilities  Small design  Only 27’000 gates + RAM

22 2000-10-11 RYP-KS Why Leon? (cont.)  Re-Configurable  Fully SPARC v8 Compatible

23 2000-10-11 RYP-KS Disadvantages With Leon?  No Support For Integer Division  DIVU – unsigned division  DIVS – signed division  New Design

24 2000-10-11 RYP-KS - The End - www.acc.umu.se/~moschler/x2000

25 2000-10-11 RYP-KS OBC Tasks Processing of Uplink Telecommand (TC) Data Stream Assemble, decode, and distribute incoming telecommands Generate Downlink Telemetry (TM) Data Stream  Collect telemetry data  Generate TM frames Provide General I/O for Command Distribution and Telemetry Data Collection

26 2000-10-11 RYP-KS OBC Tasks (cont.) Provide Processing Power for Various Tasks  Battery charging control  Calculations for non-intelligent payload  Antenna pointing (attitude controlling)  Payload and thermal control Provide With Timing Functionalities  On-Board Timer (OBT) counter  Time pulse synchronisation, by using GPS receivers  Queuing of internal spacecraft commands

27 2000-10-11 RYP-KS OBC Tasks (cont.) Provide With Autonomy Functionalities  System supervision and context switching (OS aspects)  Automatic system reconfiguration in case of system error(s)  Automatic spacecraft recovery (Sun & Earth) Bus Controlling and Peripheral Communications  Bus master  Instrument/ Payload interfacing

28 2000-10-11 RYP-KS Single Event Effects  Incoming Particles  Single Event Upset (SEU)  Single Event Latch-up (SEL)  Other Single Event Phenomena (SEP)  Technology Dependent  Silicon Wafers vs Silicon On Isolator (SOI)

29 2000-10-11 RYP-KS What Is A Real-Time System? “The correctness of a real-time system depends not only on the logical result of the computation but also on the time at which the results are produced.” – [RTSAPL]  Correct functionality, at the right time

30 2000-10-11 RYP-KS EDAC Error Detection And Correction  Scrubbing  Hamming Code d(min) = s + t + 1(I) d(min) = 2 t + 1(II)

31 2000-10-11 RYP-KS A Typical Data Handling System Data Flow

32 2000-10-11 RYP-KS ToDo  Förklara:  SCR  P/L egen intelligens som klarar sig självt, fristående från OBC. Bara busstrafik mellan  Realtidssystem och deras hårda och mjuka tidskrav  Att DHU och OBC är tätt sammanfogade i småsatelliter och att de här tituleras OBC  Hur EDAC fungerar  Förslag på EEPROM uppsättnigar och resten av ett OBDH. Kolla in WALT-projektet  Olika interruptfilosofier, typ Masked, Threshold, etc  Atomic Actions?  Pipeline  In 1950, a smart guy named Richard W. Hamming figured out a method of implementing ECC memory using the theoretical minimum number of redundant bits (this is called the Hamming Code).  FPGA  En bild på olika bitorganiseringar I minnen

33 2000-10-11 RYP-KS


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