FPGA-Based
Arcade Emulation
Danny Funk, Cory Mohling, Tony Milosch,
David Gartner, John Alexander
Advisor: Philip Jones
Client: Joseph Zambreno
Overview
Project Plan and Design
Design Challenges
2nd Semester Implementation
Final Results
Project Objective
• Goals
o Showcase the capabilities of
reconfigurable computing
platforms
o Have a system that can be used
for demonstrations
• Problem
o Demonstrating reconfigurable
computing to non-technical users
o Demonstrate capabilities in
captivating way
Conceptual Solution
• FPGA Capabilities
o Continue 09/10 Senior Design
team’s NES Emulation through
FPGA
o Entire NES and game selection
contained on single FPGA board
• Presentations
o Have wide selection of playable
games
o Create arcade machine that can be
put on display
Concept Diagram
Compact Flash Card
Boot loader
Controls
(I/O)
Functional Requirements
• Emulator must support the instruction set used by the
original NES System
• All NES-specific emulation must be performed entirely
in hardware
• Physical interface shall support 2-player arcade style
controls
Functional Requirements
• Graphical interface must allow for selection of all
available games on compact flash card
• Boot loader must read ROM files and initialize
emulator memories
• Cabinet must support 100 lb monitor, and run on
standard 120 VAC power
Non-Functional Requirements
• All emulator components shall be implemented as
individual modules
• Cabinet shall be safe for all age groups
• Users’ interaction with boot loader shall be
understandable without additional help
• Cabinet shall be a vintage style arcade cabinet to
house the system
• Cabinet shall be durable to withstand
demonstrations
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
Schedule
• Split team into 3 groups
o Emulator, Boot Loader, and Cabinet
System Decomposition
• FPGA
o
CPU
o PPU
o
Video output
o Controller Input
o Boot loader
o Audio
• Cabinet
o Physical Controls
• Joystick
• Buttons
o Monitor
System Design- Controls
• Develop an arcade style
interface for the NES
emulator
• Create wire riggings for
all the joysticks and
buttons
• Each button is mapped
directly to the controller
status register
System Design-Boot Loader
• Develop boot loader using
Microblaze Processor
provided in Xilinx tools
• Present user with easy to use
game selection screen
• Read NES Rom files from
Compact Flash
• Parse NES Rom file and load
contents into appropriate
system memory for the FPGA
• Reset back to boot loader
screen when reset is pressed
System Design
System Design- Cabinet
• Use Solid Works to design detailed cabinet
drawings
• Used feedback from client
• Purchase custom marquees
• Build out of ¾” plywood
• Detachable Control Box
• Hidden screw and nail holes
• Hinged control box for easy viewing of FPGA
System Design- Audio
• 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
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
Emulator Implementation
•
Improved functionality of past
group’s design
•
Tweaked PPU and CPU clocks
to more closely match the
original NES
•
Cleaned up existing code to
make it more understandable
for future projects
Emulator Testing
• Tested modified pieces of
emulator separately
• Ran tests found from NES
development community in
ModelSim that tested the
entire system completely
CPU Timing Failure
• When tests passed in
ModelSim, implementation
was tested for robustness on
the hardware
Sprite Test Failure
Emulator Design Revision
• True NES hardware emulation required more resources then
initially predicted
• Adopted strategy of software emulation
• New design still met original goals of the project
• Allows for over 120 games to work
Boot Loader
Implementation
• C code written to run on
PowerPC processor
• Initializes memories for
screenshots, fonts, and
music
• Program displays
metadata from compact
flash card
• Graphical interface
allows user to select
desired game from list
• Loads game data from
ROM files into emulator
memories
Boot Loader Testing
• Tested boot loader with
debug statements sent
through UART
• Debug statements used
to verify values in
memory, and
functionality of software
Cabinet Construction
• ¾” cabinet grade plywood
used for economical
strength and durability
• Kreg Joints hide screws
without compromising
strength
• Used Jim Jensen as resource
while building the cabinet
Cabinet Construction
• Control box is removable from main cabinet assembly for
demonstrations on any VGA monitor
• Wheels attached for easy transportation
• Construction presented interesting engineering challenges
Final Costs
Item
Cost
Wheels
$40.00
Speakers
$20.00
Screws
$10.00
Plywood
$90.00
Marquee
$20.00
Marquee Light
$20.00
T-Molding
$10.00
Paint/Primer
$50.00
Monitor
$500.00
Cabinet Total
$760.00
Labor – 1130hrs
$22,600.00
Final Results
Moving Forward
• Lessons Learned
o
o
o
o
o
“Take the time to learn the tools”
“Allow for ample time to acquire supplies”
“Don't set goals until you understand the full complexity of the project”
“Don't be worried about asking stupid questions”
“Have a base understanding before diving in”
• Future of the project
o Cabinet can be reused
o Networked gaming
o Advanced systems
Questions