To the 60’s and Back

Group E0: Christopher Bernard, Donovan Gionis

and Jae Woong Choi

A modern take on the Apollo Guidance Computer (AGC)

Use-Case/Applications

• Exhibition piece targeting museum displays, science exhibitions, classrooms
• Showcase Apollo Computer capabilities with an interactive DSKY
• Support space-related programs for demonstration
• Easily distributable for exhibitions, classrooms

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Quantitative Use-Case Requirements

The AGC Architecture 50Mhz, 33 instructions, 5 I/O Channels

The Peripheral uC Controller handles Key scans + LED updates at 50Hz

The DSKY PCB 14 LED Lamps, 25 Displays, 19 Key switches

Physical Dimensions Compact weight/size of 1 by 2 foot and 5 pounds

Operating Conditions Ambient temperature of 25°C. Protective Casing.

Solution Approach

• Altera DE10-Standard Dev Board w/ Cyclone V SoC
• Readily available, efficient distribution

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• AGC CPU uArch Implementation
• Defined using SystemVerilog
• Programmed via place-and-route to FPGA

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• Simulated sensor data fed to CPU input ports
• Python Script running on Linux OS on Cyclone V Core

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• User interface inspired by the original DSKY
• LED/Segment displays, Keypad on a custom PCB
• Microcontroller as interface between FPGA and DSKY

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• I2C driver on FPGA
• To communicate between microcontroller and AGC core

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• Interactive, mission-oriented assembly programs
• A kernel that constantly polls the I/O and responds to commands from the DSKY
• A python-script demo showcasing basic orbital mechanics and space missions.

System Specification

Fetch

Decode

Execute

Writeback

Implementation Plan: AGC CPU Pipeline

Implementation Plan: Simulation/Synthesis Toolchain

Implementation Plan: DSKY

Goal: DSKY will be implemented on a single PCB board (15 cm by 20 cm)

Utilize previously used and verified designs and components:

• LTP-305 Display with IS31FL3730 I2C Driver
• ESP32 Microcontroller
• Cherry MX Switches

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Suppliers are PCBWay and Digikey: Stock confirmed and budget for 2.5 units < 500 USD

Assembly: SMD using reflow oven and a solder stencil. By hand for through hole components at Techspark.

Laser cut Acrylic for final housing

Implementation Plan: Software

Microcontroller: Handle scan of keypad matrix, update lamps and numeric displays

AGC: Specific program per given Verb/Noun. Basic initialization and single-precision subroutines will be reused from Aurora 12 and Commanche055

The SoC Linux will show basic Python plots to demonstrate orbital mechanics.

Following mission programs will be implemented:

00 Monitor Mission Time 01 Hohmann Orbit Transfer�02 Orbital Plane Transfer 16 Conduct Lunar Insertion�04 Calculate Escape Velocity 05 Calculator Demonstration

http://web.mit.edu/digitalapollo/appendixa.html

Test, Verification and Validation

The AGC Architecture

• The registers state of our ISA must match a simulated AGC for all 33 instruction specific tests
• Code < 110,000 LUT’s
• Critical Path < 200 microsecond
• 0.5 Instructions per Cycle (IPC)

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The Software

• < 0.01% error of math functions SQRT, SIN, COS (from Aurora12 and Comanche055)
• < 0.1% error of orbital mechanics functions (Orbital Plane Transfer, Translunar Injection, …)

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The Hardware

• ΔTemperature < 25 °C. 3V3 Voltage Rail > 3.0V
• Verification through Microscope inspection and TruView X-ray Analyzer (Techspark)
• I2C Bus Analysis and Bandwidth (< 400kHz) check using a protocol analyzer.

Project Management

AGC is fully implemented and tested

DSKY is fully functional

Demo and uC Code is written

Full integration happens

Conclusion

• Apollo’s influence still seen to this day
• An architectural and manufacturing trailblazer
• Educational opportunities
• Demonstrate historic applications on modern equipment
• Contrast with original AGC: How far we’ve come
• Interactivity appeals to young audience
• Excitement about history and innovation
• Working examples of post-AGC innovation
• I2C, FPGA, PCB, HDL