Lag : Consoles, Emulators, FPGAs

When playing classic video games on non-original hardware, one should always be conscious for the amount of extra lag that method may offer over the original hardware.  Along with accuracy, latency is one of the most important tangible benefits (versus of using original hardware and display technology (CRTs) over emulators and current display technology (LCDs).  Latency has always existed in some form, and in this article I will give an overview on how latency has evolved over time.  

Additionally, the use of FPGA chips to simulate original hardware has become increasingly popular over the past five years.  FPGAs can offer the benefit of lower latency compared to traditional software based emulation and can offer a high degree of accuracy by using relatively inexpensive hardware.  FPGAs are not without their singular issues, and in this article I will go over some of the issues with using FPGAs as a replacement for original hardware.

RetroUSB AVS : The Affordable NES FPGA Console

RetroUSB AVS, courtesy of RetroUSB.com

The NES is undoubtedly the most cloned video game system ever, and in the 2010s FPGA technology had decreased in price to the point where it was affordable to implement retro video game systems on an FPGA.  The RetroUSB AVS was the first NES FPGA console made available to the public, and while I have discussed it before on this blog, I have not done a full review of the AVS because I never had one in my possession before.  That changed recently thanks to a friend of mine who let me borrow his for testing and review.  As this console is almost five years old at this point and is the only NES FPGA console you can currently pre-order, I think it is time to see where it has progressed and how well it has held up over the years compared to more recent competition.

FPGA NES and Famicom Solutions' Mapper Support Matrices

There have been several hardware devices released over the past four decades which play NES and Famicom games.  Any regular reader of this blog will know that the NES and Famicom have many, many different ways in which it supports memory management.  Hardware devices which support a wide variety of games use FPGAs to configure their logic to handle the various memory mappers used by NES and Famicom games.  Below I will give matrices of each device and identify the mappers it supports.  Both iNES 1.0 and NES 2.0 mappers will be identified.  None of these devices support UNIF format mappers and UNIF should be fully deprecated by NES 2.0 now.

Fixing NES Headers and Converting them to NES 2.0 : Putting Theory into Practice!

In my last blog entry, I announced the creation of an evolving database of NES ROM headers, focused on cartridge accuracy.  However, while I can make a spreadsheet for easy accessibility, spreadsheets are not the best way to organize data for use by other programs.  I cannot expect someone wanting a full set of proper NES 2.0 ROMs to manually edit the headers of over 2,900 separate files!

There has to be an easier way, right?
The task of manual fixing isn't slight.
Well, if you read further now,
I'll be happy to tell you how.

The NES and Famicom Accurate Cartridge Information Database

NES and Famicom emulation has been around for over twenty-five years.  In that time, the internal hardware has become very well documented.  NES and Famicom cartridges, on the other hand, have had a parallel journey of discovery during this time, but emulators and flash carts and FPGA devices have not always been up to date with current developments.  The core games which people enjoy with NES emulation, namely those licensed and approved by Nintendo and unlicensed games released during the NES' lifespan, sometimes suffer in emulation due not to bad dumps but a wrong information in their file header.  The header indicates what kind of hardware the game uses, but if the information in the header is wrong, out of date or missing, the game will not play or play correctly.  In this blog article I will explain how headers work, why they are necessary, the need for accurate information in them and how they have evolved over time.  Then I will describe and link to my database which contains the most accurate and up to date information for the NES and Famicom ROMs most people care about.

MiSTer - The MAME of FPGA Simulation Projects

MiSTer Fully Assembled (courtesy of MiSTer Github Wiki)

Why bother pricey FPGA simulation when there are so many excellent software emulators lying around?  The answer can be boiled down into one word : lag.  Lag is the most intractable problem with emulation and the most insidious.  Everything else, accuracy, ease of use, authenticity, a software emulator can accomplish.  But doing all that without added latency is a huge challenge and one which oftentimes cannot be met without some very expensive hardware.

An FPGA console is a modestly priced solution to lag.  FPGAs simulate original hardware at the logic level and can simulate multiple processes in parallel.  A software emulator must recreate a system alien to the hardware on which it is running and is essentially limited to processing multiple hardware events serially.  The most popular FPGA solution not made by Analogue is based on the DE-10 Nano FPGA development board.  This board is the key to the MiSTer project, a group of cores which simulate various video game consoles, computer systems and certain arcade machines under a common framework.  In this blog entry (or entries), I will dive into the world of MiSTer and discuss the aspects I like and dislike.

The CollectorVision Phoenix Part 2 - The FPGA System Built by Thieves and Sold on Disinformation

Three blog posts ago, I was rather critical of the CollectorVision Phoenix, an FPGA console which implements the ColecoVision : https://nerdlypleasures.blogspot.com/2018/10/the-collectorvision-phoenix-fpga.html  I said all that I believed needed to be said, but since then I have determined that the console was deserving of further criticism.

Before we go into the specifics of my claims, let's review the basic hardware specifications of the ColecoVision and similar systems which are based off the TMS9928A Video Display Processor (VDP).

The Analogue Mega Sg – A Preview of the Next Chapter in the FPGA "Console Wars"

Analogue Mega Sg JPN Version

Today, Analogue has made an announcement of its next FPGA retro console. This was a reveal which had been long expected. When the console was revealed as an implementation of the Sega Genesis/Mega Drive, it came as no great surprise to observers like myself familiar with Analogue’s history. Let’s explore some of that history, the specifications of the unit, what you will get for the $189.99 retail price and how this console may fare in today’s increasingly-crowded retro-console market.

The CollectorVision Phoenix - An FPGA Console Behind the Times?

The ColecoVision has a very driven fan community.  I did not own one and really do not share the love that those who do or did have, but nonetheless it is a classic gaming system that has new products and peripherals released for it.  The idea of recreating the Coleco in a modern, updated console, has long been talked about.  Currently, no less than three different groups have announced some kind of FPGA-based Coleco.  One of those project, called the CollectorVision Phoenix, is now accepting funding on kickstarter.  Let's look into the Phoenix's campaign and features and I will explain why I think you should give this FPGA console a pass.

Super Nt Review - The Ideal FPGA Console?

In the four months since the announcement of the Super Nt, there has been a lot of anticipation over the final product.  Will it ship on time?  Will it be as good as the Nt Mini?  Is it worth the money?  Can I put my original hardware away?  Now that I have had mine for about four days by the time this blog entry posts, I can try to answer those questions and give my own impressions of the system.

Analogue Nt Mini : Audio Tweaking

The Nt Mini's audio has come under some criticism from such luminaries as the My Life in Gaming channel.  Kevtris has fixed NES audio issues in Jailbreak firmwares v1.0 (MMC5 pulse pitch), v1.3 (audio sweep bug), and v1.8 (crackling static issue).  The excellent MLiG video was using v1.2, so its statements may not hold true for the latest official or jailbroken firmware.  Even so, it is hard to diagnose and fix a problem without being able to define the problem or demonstrate it in a way that would illustrate the problem to the less-technical viewer.  The MLiG video said little more than "We feel that sound might be somewhat further removed from the original hardware experience than any other aspect of the system."  

That MLiG comment is so vague as to suggest that the Nt Mini could be outputting reversed-duty cycle pulse waves like a Famiclone or too low pitched noise as with the NES Classic Edition, which it clearly does not.  Nonetheless, a more articulate critic of kevtris' APU implementation in the Nt Mini and Hi-Def NES Mod is that in certain musical tracks, the triangle and noise channels are too quiet compared to the two pulse channels.  In order to talk about this claim, first we must discuss the mixing levels of NES APU channels.

Analogue Nt Mini : Browsing the Core Store Pt 2, AV and Future Predictions

In what is likely to be the penultimate article in my Analogue Nt Mini series for some time I intend to devote some time to a few of the more interesting cores remaining in the system, then discuss the video output from the NES.  Finally, I will offer my predictions for the future.

Analogue Nt Mini - Vs. System Support

Originally I was going to post a conclusion to my Analogue Nt series, but then I had an epiphany that was too long to attach to one of the prior posts.  Yesterday I was thinking about the Nintendo Vs. System and lack of comprehensive hacks available for the games that were released for that system.  I wondered if it was possible, given the Nt Mini's extraordinary capabilities, to get the pure Vs. System ROMs running on the system through its Flashcart functionality.  About six hours of testing later, I think can present a solution that can get many of these games working now.

Analogue Nt Mini - Browsing the Core Store

In part one of my Analogue Nt Mini series, I focused on the impressions I had of the hardware and the menu from the "official" standpoint.  In the second part, I focused on the most notable feature of the Nt Mini's jailbreak firmware, the NES Flash Cart capability.  In this part, I will discuss the other area in which the Nt Mini's jailbreak firmware is very impressive, Cores recreating other video game consoles.  The Nt Mini can recreate the hardware of many classic (and not so classic) 8-bit consoles like the Atari 2600, Sega Master System and the Game Boy by loading a Core into the FPGA.  Let's talk about what happens when you want to run games with one of these cores.

Analogue Nt Mini - Jailbreak Firmware as a NES Flashcart and Dumper

In the first part of my series on the Analogue Nt Mini, I gave my thoughts on my first impressions of the device.  In this article, I will continue by diving into the features of the firmware that allow you to play NES games on your Nt Mini.  The jailbreak software adds many features to your Nt Mini, but here we will concentrate solely on the NES features.  Features related to other systems will be covered in another blog entry or two.

The Analogue Nt Mini - First Impressions

Last Thursday my Analogue Nt Mini finally arrived.  I had discussed this FPGA-based console from afar when it was first released early in the year, but had no opportunity to review one first-hand at the time.  I ordered my Nt Mini during the second run of pre-orders.  Analogue planned to ship the second batch in September, but late shipping from the factory and a surprise customs inspection later, it ended up shipping the Nt Mini in late October.  Having paid full price for an Nt Mini, $449, plus $37 in shipping, I intend to do a complete and thorough review of all the device's capabilities.  Let me start by giving my first impressions of this high end recreation of the Nintendo Entertainment System.

The Analogue Super Nt - The Day After Preview

If 2016 was the Year of the HDMI NES, with the release or pre-order availability of high quality NES HDMI devices such as the NES Classic Mini, Analogue Nt Mini and the RetroUSB AVS, then 2017 is the Year of the HDMI SNES, with the release of the SNES Classic Mini and now pre-order availability of the Analogue Super Nt.  The Super Nt was announced yesterday and I would like to gather all the available information about it here after 24 hours have passed to allow for information from multiple sources to be made available online.

RetroUSB AVS vs. Analogue Nt mini - Comparison of the Enthusiast FPGA NES Clones

Until now, any kind of accurate Nintendo NES or Famicom console had to use Nintendo's CPU and/or PPU chips, whether that console was manufactured by Nintendo, Sharp or anyone else.  While the idea of implementing a NES on an FPGA was an idea with a long history, only this year are products finally making it to market.  Here I am going to compare the features of the two announced FPGA NES implementations, the RetroUSB AVS and the Analogue Interactive Nt mini.

Console	AVS	Nt mini
Producer	RetroUSB	Analogue, LLC
Hardware Designer	Brian Parker “bunnyboy”	Kevin Horton “kevtris”
FPGA Type	Xilnix Spartan 6 XC6SLX9	Altera Cyclone V
Included	HDMI, USB Cable (mini-to-standard), Power Supply	HDMI, USB, 8Bitdo NES 30 Wireless Controller, Retro Receiver, Power Supply
Outputs	HDMI, USB	HDMI, Analog Video, RCA Stereo
Inputs	4 x NES Controller Ports, 1 x Famicom Expansion Port	4 x NES Controller Ports, 1 x Famicom Expansion Port, Microphone Input
Upgrade	USB Port	SD Card Slot
Resolution Support	720p	480p, 720p, 1080p (HDMI) 240p (analog sources only)
Video Display Support	HDMI	Composite, S-Video, Component, RGB, HDMI
Buttons	Separate Power & Reset	Combined Power & Reset
Unique Special Features	NA Scoreboard, Built-in Game Genie, Turbo-in-Software	Scalers, Famicom Expansion Audio Generation, Audio Visualizer, Famicom Microphone, NES Zapper/Famicom Gun Support (Analog video only), R.O.B/Family Robot Support (Analog video only)
Price	$185.00	$449.00
Availability	September, 2016	January, 2017

The RetroUSB AVS - A Potentially Worthy FPGA NES HDMI-Output Clone

This year, bunnyboy (Brian Parker) of retroUSB.com is going to release his long-awaited (if you are a NintendoAge forum member) AVS.  The AVS is a clone of the NES done within the programmable logic of an FPGA.  It comes in a NES-front loader influenced case, has a front loading 72-pin connector (no push down tray) and a top loading 60-pin connector for NES and Famicom games, respectively.  It only outputs HDMI at a 720p resolution.

The FPGA is a hardware recreation of the internals of the NES, namely the 2A03 CPU and the 2C02 PPU, the RAM and the glue logic required for a functioning NES.  An FPGA is a large, programmable surface mounted chip which allows the programmer to define the logic elements on the chip.  In this case, the programmer is attempting to model the CPU and PPU chips to perform an identical function to the logic contained in the discrete, through-hole chips Nintendo used.  Fortunately, these chips have been decapsulated and their dies have been imaged at very high resolution.  How they work on the hardware level is reasonably well-known, although there are some minor variations between the various revisions of each chip.