SDR 7 Jun Associated Electronics Package (AEP) Curtis Ingraham

SDR 7 Jun 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

SDR 7 Jun 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

SDR 7 Jun AEP Mechanical Layout (2)

SDR 7 Jun 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

SDR 7 Jun AEP Mechanical Layout (4)

SDR 7 Jun 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

SDR 7 Jun AEP Power System (1) DC-to-DC Converters Power Circuit Switching Current Limiting Monitoring

SDR 7 Jun 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

SDR 7 Jun 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

SDR 7 Jun 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

SDR 7 Jun AEP Data Processing Unit (DPU) (1) DPU Functions –Receives Commands –Sends Status –Sends Telemetry –Manages Mass Memory –Manages Power System –Controls Instrument

SDR 7 Jun 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

SDR 7 Jun AEP Data Processing Unit (DPU) (3) DPU Block Diagram

SDR 7 Jun 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

SDR 7 Jun 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

SDR 7 Jun 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

SDR 7 Jun 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

SDR 7 Jun AEP Mass Memory (MM) (2) MM Block Diagram

SDR 7 Jun 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

SDR 7 Jun AEP Mass Memory (MM) (4) Buffer Allocation –Controlled by DPU –Circular or Linear –Continuous Fill –Freeze on Event –Anywhere in MM –Several Binary Sizes

SDR 7 Jun 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

SDR 7 Jun AEP Mass Memory (MM) (6) Imager MM Interface –Fast, Sequential DMA –Write Only –Circular or Linear Buffer

SDR 7 Jun 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

SDR 7 Jun AEP Imager Interface Controlled by DPU CDI Imager Status Start Signal from DPU or Trigger Fast Transfer to Mass Memory Buffers in Mass Memory

SDR 7 Jun 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

SDR 7 Jun AEP Array Photometer Interface +28 Volts from Power Controller DMA Channel to Mass Memory Circular Buffer in Mass Memory Interface Characteristics TBD

SDR 7 Jun AEP Digital Signal Processor (DSP) Fast, Direct Access to Mass Memory Command Block Interface with DPU Details per NCKU