Associated Electronics Package (AEP)

1. Associated Electronics Package (AEP) • Associated Electronics Package (AEP) Curtis Ingraham

2. Associated Electronics Package (AEP) • Associated Electronics Package (AEP) • Mechanical Layout • Thermal Control • Power System • Data Processing Unit • Mass Memory • Imager Interface • Spectrophotometer Interface • Array Photometer Interface • Digital Signal Processor

3. AEP Mechanical Layout (1) • Seven Subassemblies • Subass’y = PCB plus Aluminum Frame • PCB Frame = Slice of Enclosure • Top and Bottom Covers • Bottom Subass’y has Mounting Ears • Ten Skewer Rods Secure Stack

4. AEP Mechanical Layout (2)

5. AEP Mechanical Layout (3) • I/O Connectors in Frame at Board Edge • Stacking Connectors for Inter-Board Connections • No Motherboard Needed • Simple Mechanical Arrangement • Fewer Connections • Short Signal Paths • Good Radiation and EMI Shielding • Good Thermal Path • Easy Assembly/Disassembly • Allows Incremental Development

6. AEP Mechanical Layout (4)

7. AEP Thermal Control • Heat Transfer by Conduction • Component Leads to PCB • PCB to Frame • Frame to Deck • Hottest Subassembly at Deck • Hottest Components at board edge near Frame • At Least One Thermistor per Subass’y • Each Thermistor at Hottest Component

8. AEP Power System (1) • DC-to-DC Converters • Power Circuit Switching • Current Limiting • Monitoring

9. AEP Power System (2) • Low Voltage Power Supply (1) • Input Filter • d.c.-to-d.c. Converters • Modular Devices 2680R Family • Dual Redundant +/-12 volt Converter • Dual Redundant +5 volt Converter • Independent Inputs • Shunt-Wired Outputs • Ground Isolation • Input Range Exceeds S/C Spec • Output Filter

10. AEP Power System (3) • Low Voltage Power Supply (2) • Input Current Monitors • Relay-Switched 28-V to Array Photometer • Nominal or Redundant Power to Array Photometer • Low-Z Thermal Path to Deck • Two Temperature Monitors • Contained in Shielded Cavity • Proven In IMAGE FUV Instrument

11. AEP Power System (4) • Power Controller • Receives d.c. Power from LVPS • Individually Switched Power Services • Flexible Power Control • Able to Isolate Abnormal Loads • Voltage and Current Monitors • Valuable Diagnostic Information • Approx. 106 Analog Housekeeping Channels • Fold-back Current Limiting • Protects Load • Protects Power System • Two Thermal Monitors

12. AEP Data Processing Unit (DPU) (1) • DPU Functions • Receives Commands • Sends Status • Sends Telemetry • Manages Mass Memory • Manages Power System • Controls Instrument

13. AEP Data Processing Unit (DPU) (2) • DPU Organization • 8085 CPU • Rad Hard, Simple, Byte wide, Low Power • Proven in Space Missions • 16 Kilobytes PROM • Baseline Flight Software • Power Switched (High Power) • 128 Kilobytes SRAM • Flight Software Execution • Settings, Stack, Tables • Telemetry DMA Source

14. AEP Data Processing Unit (DPU) (3) • DPU Block Diagram

15. AEP Data Processing Unit (DPU) (4) • DPU Organization (Continued) • 128 Kilobytes EEPROM • Operating Parameter Tables • Static Settings • Alternate Flight Software Versions • Command Receiver • Status Telemetry Transmitter • Science Telemetry Transmitter • Command & Data Interface

16. AEP Data Processing Unit (DPU) (5) • DPU Organization (Continued) • I/O for Instrument Control • High Voltage Control • Bank Switching and Memory Map • Watchdog Reset Timer • Diagnostic Test Port

17. AEP Data Processing Unit (DPU) (6) • Command & Data Interface • Three-Wire Serial Interface (Data, Clock, Strobe) • Eight-Bit Address Plus 16-Bit Data • 2 Mb/s; about 14 microseconds per command

18. AEP Mass Memory (MM) (1) • One Gigabit • Static RAM • 128 Mbytes • Accessible by 8- or 32-Bit Words • Stores Raw and Compressed Science Data • Multi-Port • DSP • DPU • Array Photometer • Spectrophotometer • Imager

19. AEP Mass Memory (MM) (2) • MM Block Diagram

20. AEP Mass Memory (MM) (3) • Low Power • Error Detection and Correction • Automatic 1-bit Error Correction • 2-bit Error Detection • Error Counters • Latchup Detection • Power Isolation? • Controlled by DPU

21. AEP Mass Memory (MM) (4) • Buffer Allocation • Controlled by DPU • Circular or Linear • Continuous Fill • Freeze on Event • Anywhere in MM • Several Binary Sizes

22. AEP Mass Memory (MM) (5) • DSP MM Interface • Fast, Memory Mapped, Direct Access, Read/Write • High Priority • DPU MM Interface • Slower, Memory Mapped, Direct Access, Read/Write • Low Priority • Bank Switched into 8085 Memory Space • Telemetry by PCVF Blocks

23. AEP Mass Memory (MM) (6) • Imager MM Interface • Fast, Sequential DMA • Write Only • Circular or Linear Buffer

24. AEP Mass Memory (MM) (7) • Spectrophotometer MM Interface • Fast, Sequential DMA • Write Only • Circular Buffer • Array Photometer MM Interface • Fast, Sequential DMA • Write Only • Circular Buffer

25. AEP Imager Interface • Controlled by DPU CDI • Imager Status • Start Signal from DPU or Trigger • Fast Transfer to Mass Memory • Buffers in Mass Memory

26. AEP Spectrophotometer Interface • Six Channels • Integrates Charge from PMT • 12-bit A/D Converter per Channel • Sampled at 10 kHz per Channel • Continuously Fed to MM Circular Buffer • Digital Processing of Selected Channel for Sprite Trigger • Adjustable Trigger Threshold

27. AEP Array Photometer Interface • +28 Volts from Power Controller • DMA Channel to Mass Memory • Circular Buffer in Mass Memory • Interface Characteristics TBD

28. AEP Digital Signal Processor (DSP) • Fast, Direct Access to Mass Memory • Command Block Interface with DPU • Details per NCKU