FPGA NES Looks Sharp On Perfboard

March 18, 2019 by Lewin Day 4 Comments

FPGAs are wonderful things, packed with logic cells that can be reconfigured as your heart desires. They excel at signal processing, anything requiring speed, and recreating vintage hardware. In that vein, [Jon Thomasson] decided to bring back the original Nintendo Entertainment System, in perfboard form.

The build uses a Spartan 6 from Xilinx, which [Jon] uses in the form of his own development board design. The NES core is courtesy of code by [Brian Bennett], sourced from Github. Games are loaded from an SD card by a Parallax Propeller, which passes the data to the FPGA over a serial connection. Display is on a sharp 800×480 LCD, with the 4:3 video output of the NES being displayed in a pillarboxed fashion.

The project is assembled on perfboard, with a pleasing handheld formfactor. Control is via tactile pushbuttons in the classic NES layout. Current draw is approximately 400 mA, giving a runtime of around 5 hours when running off four AA batteries.

We’ve seen the venerable NES implemented on FPGA platforms before. As development boards get cheaper and devices get more capable, expect to see ever more complex systems being implemented. Video after the break.

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Component Video For The Commodore 64

March 10, 2019 by Brian Benchoff 36 Comments

Of all the retro systems, the Commodore 64 had the best video system. The VIC-II chip in the C64 was the best example of why Commodore was the best, but in terms of video output, the C64 was still a consumer device: the only output was S-video, or composite video, or something like it. The professional stuff uses YPbPr, an RGB video signal that separates the red, green, and blue colors. On a modern LCD, the difference between composite and YPbPr is noticeable, and if you’re going to run your C64 on the big screen, it would be very helpful to use a professional video standard.

In an effort to bring the C64 into the future, [c0pperdragon] created an FPGA-based modification for the VIC-II chip. The end result is getting YPbPr signals directly from the computer, and outputting it to a TV in glorious 480p.

Inside the Commodore 64, the VIC-II creates the chrominance signal in a way that is impossible to convert it back to any form of RGB. The solution to get RGB out of this information is to listen in to 22 pins of the VIC-II to determine what signals it intends to generate. This is done with a smallish Altera FPGA connected to the VIC-II through a ribbon cable. On the FPGA, the luminescence and all the color information is generated, then converted into true YPbPr. For the complete mod, the RF modulator is removed, and the original A/V jack is still functional. This is effectively a very in-depth mod that rids the C64 of the TV connector and channel selector (that no one uses anymore) and replaces it with a professional-grade video output.

When it comes to C64 mods, we thought we’ve seen it all. We’ve seen C64s resurrected from the dead, and we’ve seen drop-in replacements for the SID that still don’t have working filters oh my god. This is on another level. This is using FPGAs to drag the C64 into the modern era, and if you don’t care about the rusting RF box, it’s a reversible mod.

FPGA Brings Arduboy To The Game Boy Advance

February 21, 2019 by Tom Nardi 8 Comments

Hackaday readers are perhaps familiar with the Arduboy, an open source handheld gaming system that aims to combine the ease of Arduino development with the seething nostalgia the Internet has towards the original Nintendo Game Boy. While not quite the same as getting one of your games published for a “real” system, the open source nature of the Arduboy platform allows an individual to develop a game playable on a commercially manufactured device.

While the Arduboy hardware itself is actually quite slick, that hasn’t stopped people from trying to bring its games to other pieces of hardware. Now thanks to the efforts of [uXe], the Game Boy Advance is well on its way to becoming Arduboy compatible, in a way bringing the whole project full circle. Assuming this gadget becomes a commercial device (it sounds like that’s still up in the air), Arduboy developers will be able to proudly play their creations on the final and objectively best entry into the Game Boy line.

Getting to this point has been something of an adventure, as documented in a thread from the Arduboy forums. Members of the community wondered what it would take to get Arduboy games running on a real Game Boy, but pretty quickly it was decided that the original beige brick model wasn’t quite up to the task. Eventually its far more capable successor the Game Boy Advance became the development target, and different approaches were considered for getting existing games running on the platform.

While there were some interesting ideas, such as using the GBA’s link port to “feed” the system games over SPI, in the end [uXe] decided to look into creating an FPGA cartridge that would actually run the Arduboy games. In this scenario, the GBA itself is basically just being used as an interface between the FPGA and the human player. In addition to these low-level hardware considerations, there was considerable discussion about the more practical aspects of bringing the games to the new hardware, such as how to best scale the Arduboy’s 128 x 64 output to the GBA’s 240 × 160 screen.

As demonstrated in the videos after the break, [uXe] now as all the elements for playing Arduboy games on the GBA in place, including the ability to disable full screen scaling by using the shoulder buttons. Now he just needs to shrink the hardware down to the point it will fit inside of a standard GBA cartridge. Beyond that, who knows? Perhaps the appeal of being able to run Arduboy games on a real Game Boy is enough to warrant turning this hack into a new commercial product.

Thanks to a hardware swap we’ve seen Arduboy games played on the Dreamcast VMU, and [uXe] himself previously grafted Arduboy-compatible hardware into an original Game Boy, but being able to play these games on an unmodified Game Boy Advance obviously has its own appeal. At the very least, it will be a bit more ergonomic than using a hacked classroom gadget.

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FPGA Makes Digital Analog Computer

February 14, 2019 by Al Williams 6 Comments

When you think of analog computing, it’s possible you don’t typically think of FPGAs. Sure, a few FPGAs will have specialized analog blocks, but usually they are digital devices. [Bruce Land] — a name well-known to Hackaday — has a post about building a digital differential analyzer using an FPGA and it is essentially an analog computer simulated on the digital fabric of an FPGA.

Whereas traditional analog computers use operational amplifiers to do mathematical integration, on the FPGA [Land] uses digital summers The devices simulate a system of differential equations, which can be nonlinear.

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Building A RISC-V Desktop

February 11, 2019 by Brian Benchoff 15 Comments

If you want to talk about RISC-V, the Open Source instruction set for CPUs, you’re probably talking about microcontrollers. You can buy small but powerful RISC-V micros on par with an ARM Cortex-M4 right now. Deep in the pipeline are cores for something resembling SoCs, the kind you’d find in desktop NAS solutions, maybe a few routers, and smart TVs. This is great and all, but our idea of a ‘computer’ is still a desktop. When is the Open instruction set desktop coming? Well, it’s here right now. [Andrew Back] built a RISC-V desktop computer. It runs Linux, it comes in a case, it has HDMI and USB, there’s a graphics card in there somewhere, and it works. This is a desktop, running with a RISC-V core.

The core of this build is the HiFive Unleashed, a Linux-capable board from SiFive, makers of the first (production) RISC-V microcontroller. This board uses the Freedom U540 SOC built with a 28nm process, has 8GB of DDR4, and 32MB of Flash. For a board built on an Open archetecuture this is impressive, but it comes at a cost: the HiFive Unleashed ran for $1000 during its crowdfunding campaign.

But a board with an Open CPU does not a desktop make. You need peripheral IO, maybe a few PCIe, and hopefully a SATA interface. This problem has been solved by Microsemi with an Expansion board for the HiFive Unleashed. It includes a big ‘ol FPGA and all the connectors you could use. It also costs $2000.

With most of the parts ready to go, a few buttons, M.2 PCIe and SATA SSD storage, a graphics card, and a nice acrylic case were added. Thanks to Western Digital, building Linux was as easy as building Linux, and you end up with a desktop computer with a RISC-V brain.

Compared to a bog-standard ‘gaming machine’, this is an expensive build. The quick and dirty ballpark for the price is somewhere around $4000 USD for a machine that will let you check your Facebook. There’s a video of the machine running, you can check that out below.

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Two Joysticks Talk To FPGA Arcade Game Over A VGA Cable

February 11, 2019 by Dan Maloney 5 Comments

We really love when hacks of previous hacks show up in the tip line. It shows how the hardware hacking community can be a feedback loop, where one hack begets the next, and so on until great things are everywhere. This hacked joystick port for an FPGA Pac Man game is a perfect example of that creative churn.

The story starts with Pano Man, a version of the venerable arcade game ported to a Pano Logic FPGA thin client by [Skip]. We covered that story when it first came out, and it caught the attention of [Tom Verbeure], particularly the bit in the GitHub readme file which suggested there might be a better way to handle the joystick connections. So [Tom] took up the challenge of using the Extended Display Identification Data (EDID) circuit in the VGA connector to support an Atari 2600 joystick. The EDID system is an I²C bus, so the job needed the right port expander. [Tom] chose the MCP23017, a 16-bit device that would have enough GPIO for dual joysticks and a few extra buttons. Having never designed a PCB before, [Tom] fell down that rabbit hole for a bit, but quickly came up with a working design, and then a better one, and then the final version. The video below shows it in action with Pano Man.

We think the creative loop between [Skip] and [Tom] was great here, and we can’t wait to see who escalates next. And it’s pretty amazing how much IO can be stuffed over two wires if you have the right tools. Check out this VGA sniffing effort to learn more about EDID and I²C.

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Hidden LED Video Wall At The Oregon Museum Of Science

February 10, 2019 by Lewin Day 10 Comments

Glowing and blinking things are some of our favourite projects around these parts, and the bigger, the better. [Thomas] wrote to us recently to share the design and construction of a large LED wall at the Oregon Museum of Science, and the results are nothing short of impressive.

The concept involved a large LED wall that would be completely hidden when switched off. The team decided to approach this by hiding high-brightness LED panels using APA102 strings behind milky-white plexiglass panels covered with a woodgrain print. The screen has a total of 90,000 pixels, arranged in a 408×220 resolution display.

A lot of bespoke LED displays have some pre-coded patterns, or perhaps some basic reactive features. In this case, FPGA grunt was brought to bear on the problem and the display accepts standard HDMI input. Four Spartan 6 Mojo FPGA boards split up the task of addressing the panels, each receiving the same HDMI signal, but only crunching the pixels relevant to their area of the display. To make sure clean SPI signals get to each panel, special RS485 driver chips are used to send the signal over a differential pair from the FPGA, before breaking the signal back out to standard SPI at the destination.

Building such a large display takes special techniques, and [Thomas] notes that the help of a local construction company was imperative to making the construction of the final video wall look easy. It’s always interesting to see what goes into these large installations. Sometimes, a major build can even clear out world stocks of important components.