Extended Analog Computer

Architectural Overview

• Block Diagram
• Digital Interface (eac1-eac4): Each EAC has a 10Mb ethernet interface for communication. There are currently four EAC systems. They are named eacx.cs.indiana.edu (where x=1-4).
• Programmable Current Sources (dac 0-7): Each of the 8 programmable current sources has a range of 0-1mA.
• Programmable Current Sinks (dac 8-15): Each of the 8 programmable current sinks has a range of 0-1mA.
• Lukasiewicz Logic Array (lla 0-5, functions 1-27): Each of the 6 fully-continuous LLA circuits can be programmed to generate one of 27 different piecewise linear functions. An lla takes current as an input and delivers an output current based on applying the programmed function to the input. Each LLA provides it's result as both a sink and source output.
• Connector Block: A connector block is used to allow flexibility in the arrangement of the sources,sinks, and LLAs.
• Conductive Substrate: There are currently two types of conductive substrate used by the EAC.
• Silicon: 28 I/O Probes arranged radially. Substrate voltage can be reported from each probe point
• Conductive Foam: 9x13 probe matrix arranged in a cartesian grid. Substrate voltage can be reported from every other pin (5x7 array of voltage probes)

User Interface

• Overview
• Command Language
• Pinouts
• EAC
  • EAC Schematic Sheet 1
  • Drawing Showing Location of Components on the EAC Board
  • Interface Pins in Tabular Form
• Conductive Sheet - When using the conductive foam substrate, the voltage sense pins are arranged in a 5x7 grid starting at PG1 on the schematic. For layout purposes, the pins have been grouped in 4x4 blocks of pins labeled PGx. The schematic shows every other pin being connected to signals labeled "voltage_sense(y)" where y represents the A/D channel. For example, voltage_sense(10) is A/D channel 10.
  • Conductive Substrate Schematic Sheet 1
  • Drawing Showing Location of Components on the Substrate Board

Example Perl Scripts

• Utilities
• Write DAC Current
USAGE: write_dac_current [eac_name] [dac] [dac_current_mA]
EXAMPLE: write_dac_current eac1 2 0.5
Command DAC 2 on EAC 1 to output 0.5mA


• Write LLA Function
USAGE: write_lla_function [eac_name] [lla] [function]
EXAMPLE: write_lla_function eac1 2 25
Sets function 25 on LLA 2 of EAC 1


• Report Sheet Voltages
USAGE: report_sheet_voltages [eac_name] [grid_data_file]
EXAMPLE: report_sheet_voltages eac1 5x7_data.txt
Returns a file with a 5x7 matrix of sheet voltages reported in volts


• Report LLA Current
USAGE: report_lla_current [eac_name] [lla]
EXAMPLE: report_lla_current eac1 2
Returns the input and output current reported in mA from LLA 2 on EAC 1.


• Applications
• XOR - low current version for conductive foam (eac1 and eac3)
USAGE:xor_low [eac_name] [lla_input_current_data_file] [lla_output_current_data_file] [step_size]
EXAMPLE: xor_low eac1 xori.dat xoro.dat 200
Returns two 200x200 files (xori.dat,xoro.dat) with samples reported in (mA)


• XOR - high current version for silicon substrate (eac2 and eac4)
USAGE:xor_high [eac_name] [lla_input_current_data_file] [lla_output_current_data_file] [step_size]
EXAMPLE: xor_high eac1 xori.dat xoro.dat 200
Returns two 200x200 files (xori.dat,xoro.dat) with samples reported in (mA)


• XOR - example makefile to run and plot XOR on eac3


• Triangle Wave Current Source
USAGE: triangle_source [eac_name] [dac] [steps_per_cycle]
EXAMPLE: triangle_source eac1 2 20
Repeatedly outputs triangle wave current on DAC 2 of EAC 1 at 20 steps/cycle



Reference

• Perl Tutorials
• gnuplot introduction

Lab Support Contact

Bryce Himebaugh

CSG Staff

bhimebau@cs.indiana.edu

LH430B

855-6984