SDR 7 Jun 2000 1

Associated Electronics Package (AEP)

• Associated Electronics Package (AEP)

Curtis Ingraham

SDR 7 Jun 2000 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

SDR 7 Jun 2000 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

SDR 7 Jun 2000 4

AEP Mechanical Layout (2)

SDR 7 Jun 2000 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

SDR 7 Jun 2000 6

AEP Mechanical Layout (4)

SDR 7 Jun 2000 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

SDR 7 Jun 2000 8

AEP Power System (1)

• DC-to-DC Converters

• Power Circuit Switching

• Current Limiting

• Monitoring

SDR 7 Jun 2000 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

SDR 7 Jun 2000 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

SDR 7 Jun 2000 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

SDR 7 Jun 2000 12

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 2000 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

SDR 7 Jun 2000 14

AEP Data Processing Unit (DPU) (3)

• DPU Block Diagram

SDR 7 Jun 2000 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

SDR 7 Jun 2000 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

SDR 7 Jun 2000 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

SDR 7 Jun 2000 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

SDR 7 Jun 2000 19

AEP Mass Memory (MM) (2)

• MM Block Diagram

SDR 7 Jun 2000 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

SDR 7 Jun 2000 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

SDR 7 Jun 2000 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

SDR 7 Jun 2000 23

AEP Mass Memory (MM) (6)

• Imager MM Interface– Fast, Sequential DMA

– Write Only

– Circular or Linear Buffer

SDR 7 Jun 2000 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

SDR 7 Jun 2000 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

SDR 7 Jun 2000 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

SDR 7 Jun 2000 27

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 2000 28

AEP Digital Signal Processor (DSP)

• Fast, Direct Access to Mass Memory

• Command Block Interface with DPU

• Details per NCKU