FPGA-Based
Arcade Emulation
Danny Funk, Cory Mohling, Tony Milosch,
David Gartner, John Alexander
Advisor: Philip Jones
Client: Joseph Zambreno
Project Objective
• Goal
o Showcase the capabilities of
reconfigurable computing
platforms
• Problem
o Continue 09/10 Senior Design
team’s NES Emulation through
FPGA
o Create Arcade Machine that
can be put on display
Conceptual Sketch
Boot Loader
Controls
(I/O)
Functional Requirements
FPGA
• FR 1.1 – All NES specific emulation must be
performed entirely in hardware.
• FR 1.2 – Emulation must be contained within the
FPGA Xilinx570X board.
Functional Requirements
Emulator
• FR 2.1 – Emulator must support the instruction set
used by the original NES system.
• FR 2.2 – Emulator must be able to run a NES ROM file
from an outside source.
Functional Requirements
I/O - Controls
• FR 3.1.1 – Emulator must accept input from arcade
style controls.
• FR 3.1.2 – Emulator must accept input from NES
controllers.
• FR 3.1.3 – Emulator must respond to controller input
with the same latency as the original NES.
• FR 3.1.4 – Emulator must accept controls for up to
two players.
Functional Requirements
I/O – Video
• FR 3.2.1 – System must be able to display images to
a connected display.
• FR 3.2.2 – System must output video to a screen at
the original NES frame rate.
• FR 3.2.3 – Emulator must use a color palette
consistent with the original NES color palette.
• FR 3.2.4 – Must be compatible with VGA Output.
Functional Requirements
I/O – Audio
• FR 3.3.1 – Emulator must generate background
music for NES games.
• FR 3.3.2 – Emulator must generate sound effects
with the same latency as the original NES.
Functional Requirements
Boot Loader
• FR 4.1 – Must be able to display a selectable list of
games to the connected display.
• FR 4.2 – Must be able to load the selected ROM file
to the emulator without modifying the FPGA.
Functional Requirements
Cabinet
• FR 5.1 – Cabinet must be able to support a 103 lb.
monitor.
• FR 5.2 – Cabinet must accept a standard 120 VAC
source to power the system.
Non-Functional Requirements
• NFR 1.1 – Emulator must be contained within a
removable control box.
• NFR 1.2 – All components of the emulator should be
implemented as independent modules.
• NFR 1.3 – The Cabinet should be sturdy enough to
resist collapse under normal usage.
• NFR 1.4 – The Cabinet should be able to fit through
a 3’0” wide doorway.
• NFR 1.5 – Users should be able to easily understand
how to play a game without off-screen instructions.
Considerations
• Constraints
o System has to be designed around NES ROM files and NES instruction set
o Only a limited amount of logic on FPGA board
o Cabinet should be able to be moved from building to building on campus
• Technology
o Using new monitor technology with old NES
o Interfacing with arcade controls
Market Survey
• Another project currently exists (Veri NES). The
source is not available.
• Various software emulators are available and will
help with understanding the NES.
• Researched how similar arcade cabinets have
been built.
• Took measurements of button layouts from original
arcade cabinets.
Risks and Mitigations
• Unfamiliarity with FPGA coding and NES Architecture
o Research with assistance of advisor
• Audio may require CPU to be rewritten
o Start early on Audio
• Unforeseen extra design required
o Start Early on FPGA work
• Little experience with woodworking
o Seek outside advice and make detailed blueprints
Cost Estimate
Item
CABINET
castor wheels
speakers
4'x8' plywood
screws/fasteners
paint/primer
arcade monitor
coin slots
CONTROLS
joystick
button
Trackball
ELECTRONICS
FPGA
misc cables
Price per unit
quantity total price
Cabinet total
$5.10
$18
$26
$30
$30
$500
$33
4
2
3
$21
$3
$115
2
10
1
1
1
$20.4
$36
$78 Controls total
$30
$30
$500
$33
$727.4
$187
Controls Total
$42
$30
$115
$187
Electronics total
$170
$15
1
$170
$15
$185
Materials total
$1099.40
Labor
$20
1500
Grand Total: $31099.40
$30000
System Decomposition
• Breakdown
o FPGA
• CPU
• PPU
• Video output
• Controller Input
• Boot loader
• Audio
o Cabinet
• Physical Controls
o Joystick
o Buttons
• Monitor
System Design
• Controls
o Develop an arcade style interface for the NES emulator
o Create wire riggings for all the joysticks and buttons
o Each button is mapped directly to the controller status register
System Design
• Boot loader
o Develop Boot loader using Microblaze Processor provided in Xilinx
tools
o Present user with easy to use game selection screen
o Read NES Rom files from Compact Flash
o Parse NES Rom file and load contents into appropriate system
memory for the FPGA
o Reset back to Boot loader screen when reset is pressed
System Design
System Design
• Cabinet
o Use Solid Works to design detailed cabinet drawings
o Purchase custom marquees
o Build out of ¾” plywood
o Detachable Control Box
o Coin Door
o Hidden screw and nail holes
System Design
• Audio
o
o
o
o
Write audio module that generates audio
Connect audio module to CPU
Map all audio related instructions from the CPU to the module
Connect audio module to AC97 to produce sound output
o “A Implementation of the NES Audio Processing Unit” by Cedomir
Segulja and Bill Dai
System Design
• PPU
o Map CPU memory to PPU registers to allow for game scrolling
o Implement Memory mappers to allow for more games to be
played
o PPU is implemented using a 14 stage finite state machine to
render each pixel
o Each pixel is stored in a buffer that is then sent to the VGA output
Test Plan
• Test as we go
o After each step, make sure that the game plays as expected
• Simulate
o Simulate incremental builds with ModelSim to ensure system works
as expected
• Final Test
o Ensure all functional requirements are met, and debug as
necessary.
Current Status
•
•
•
•
•
•
Side Scrolling – 80%
Control Input – 95%
Boot Loader – 40%
Cabinet Design – 100%
Cabinet Construction – 0%
Audio – 0%
Next Semester Plan
•
•
•
•
Start Construction of the Cabinet
Start implementing Audio
Complete implementation of boot Loader
Continue working on debugging current
implementation so more games can run.
Task Responsibility
Name
Tasks(s)
Total Hours
John Alexander
Boot loader
68.5
Danny Funk
Cabinet Design
70
David Gartner
Controller Input / Boot loader
63
Tony Milosch
Scrolling, Debug current implementation
104.5
Cory Mohling
Scrolling, Debug current implementation
105.5
Questions