fpga

535 Articles

A Modern 386 Development Board

November 17, 2015 by 49 Comments

Some readers out there probably have nostalgic feelings for their first 386 based PC, the beeps and hisses of the modem, and the classic sound of a floppy drive’s stepper motor. Perhaps that turbo button that we could never quite figure out.

If you want the power of a 386 processor today, you’re in luck: [Pierre Surply] has developed a modern development board for the 80386SX CPU. This board is based on a 386 processor that comes in a LQFP package for “easy” soldering, and an Altera Cyclone IV FPGA.

To allow the CPU to run, the FPGA emulates the chipset you would usually find on a PC motherboard. The FPGA acts as both a bus controller and a memory controller for the CPU. On the board, there’s an SRAM chip and internal memory on the FPGA, which can be accessed through the 386’s bus access protocol.

The FPGA also provides debugging features. A supervisor application running on the FPGA gives debugging functionality via a FTDI USB to UART chip. This lets you control operation of the CPU from a PC for debugging purposes. The FPGA’s memory can be programmed through a JTAG interface.

The project is very well documented, and is a great read if you’re wondering how your old 386 actually worked. It can even be hand soldered, so the adventurous can grab the design files and give it a go. The francophones reading can also watch the talk in the video below.

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Stuffing Macs Into FPGAs

October 24, 2015 by 23 Comments

A few years ago, [Steve] of Big Mess ‘O Wires fame stuffed one of the first Macintosh computers into an FPGA. While the project worked and was able to run System 6 on a virtual CPU, there were a few problems: it wasn’t exactly stable, and there was no support for a keyboard, sound, SCSI, or serial ports.

Now, there’s a new tiny FPGA board around, and this one is perfectly designed to fit the original Macintosh on it. It’s much more stable, and there is a floppy disk emulator on the horizon, just so you won’t have to deal with all those 400k 3.5″ disks anymore.

[Steve]’s brand new Mac Plus is based on the MiST board, an FPGA board that was originally designed to emulate the first Amigas and the Atari SE on an FPGA and a separate ARM CPU. There’s already been a lot of classic computers ported to the MiST, and the classic all-in-one Macs are the last project that’s left.

In the video below, you can see the MiST board running the classic System 6 at SVGA resolution. That means MacPaint and Shufflepuck in one compact board using modern hardware.

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FPGAs For The Raspberry Pi

October 18, 2015 by 101 Comments

FPGA development has advanced dramatically in the last year, and this is entirely due to an open-source toolchain for Lattice’s iCE40 FPGA. Last spring, the bitstream for this FPGA was reverse engineered and a toolchain made available for anything that can run Linux, including a Raspberry Pi. [Dave] from Xess thought it was high time for a Raspberry Pi FPGA board. With the help of this open-source toolchain, he can program this FPGA board right on the Raspberry Pi.

The inspiration for [Dave]’s board came from the XuLA and StickIt! boards that give the Raspberry Pi an FPGA hat. These boards had a problem; the Xilinx bitstreams had to be compiled on a ‘real’ PC and brought over to the Raspberry Pi world. The new project – the CAT Board – brings an entire FPGA dev kit over to the Raspberry Pi.

The hardware for the CAT Board is a Lattice iCE-HX8K, 32 MBytes of SDRAM, a serial configuration flash, LEDs, buttons, DIP switches, grove connectors, and SATA connectors (although [Dave] is just using these for differential signals; he doesn’t know if he can get SATA hard drives to work with this board).

Despite some problems with his board house, [Dave] eventually got his FPGA working, or at least the bitstream configuration part, and he can blink a pair of LEDs with a Raspberry Pi and programmable logic. The Hello World for this project is done, and now the only limit is how many gates are on this FPGA.

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Flying High With Zynq

October 14, 2015 by 10 Comments

[Aerotenna] recently announced the first successful flight of an unmanned air vehicle (UAV) powered by a Xilinx Zynq processor running ArduPilot. The Zynq is a dual ARM processor with an onboard FPGA that can offload the processor or provide custom I/O devices. They plan to release their code to their OcPoC (Octagonal Pilot on a Chip) project, an open source initiative that partners with Dronecode, an open source UAV platform.

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Open Source FPGA Pi Hat

October 10, 2015 by 14 Comments

Over on Hackaday.io, [Dave Vandenbout] has posted the CAT board, a Raspberry Pi daughterboard hat that features a Lattice FPGA, 32 MB of RAM, EEPROM, and a few Grove and PMOD connectors. The CAT takes advantage of the open source tool chain available for Lattice including the Python-based MyHDL (although, you could just use Verilog directly, if you prefer) and Icestorm. One interesting point: you can run the tool chain on the Raspberry Pi, resulting in a self-contained and largely portable FPGA development environment.

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ARMs And FPGAs Make For Interesting Dev Boards

October 7, 2015 by 121 Comments

Tiny Linux computers are everywhere, and between BeagleBones, Raspberry and Banana Pis, and a hundred other boards out there, there are enough choices to go around. There is an extremely interesting ARM chip from Xilinx that hasn’t seen much uptake in the field of tiny credit-card sized computers: the Zynq. It’s an ARM Cortex-A9 coupled with an FPGA. It’s great for building peripherals that wouldn’t normally be included on a microcontroller. With Zynq, you just instantiate the custom bits in the FPGA, then interface them with a custom Linux driver. Thanks to CrowdSupply, there’s now a board out there that brings this intriguing chip to a proper development platform. It’s called the Snickerdoodle, and if you’ve ever wanted to see the capabilities of an FPGA tightly coupled to a fast processor, this is the board to watch.

The core of the Snickerdoodle is a Xilinx Zynq that features either a 667 MHz ARM Cortex A9 and a 430k gate FPGA (in the low-end configuration) or an 866 A9 and 1.3M gate FPGA. This gives the Snickerdoodle up to 179 I/O ports – far more than any other tiny Linux board out there.

Fully loaded, the Snickerdoodle comes with 2.4 and 5GHz WiFi, Bluetooth, 1GB of RAM, and an ARM Cortex A9 that should far surpass the BeagleBone and Raspberry Pi 2 in capabilities. This comes at a price, though: the top-shelf Snickerdoodle has a base price of about $150.

Still, the power of a fast ARM and a big FPGA is a big draw and we’re expecting a few more of these Zynq boards in the future. There are even a few projects using the Zynq on hackaday.io, including one that puts the Zynq in a Raspberry Pi-compatible footprint. That’s exceedingly cool, and we can’t wait to see what people will build with a small, fast ARM board coupled to an FPGA.

Vintage BBC Computer Gets FPGA Buddies

October 3, 2015 by 10 Comments

The BBC Microcomputer System (or BBC Micro) was an innovative machine back in the early 1980’s. One feature that impressed reviewers was a “tube” interface that allowed the machine to become an I/O processor for an additional CPU. When the onboard 6502 became too slow, it could become a slave to a Z-80 or even an ARM processor. The bus was actually useful for any high-speed device, but its purpose was to add new processors, a feature Byte magazine called “innovative.”

[Hoglet67] has released a very interesting set of FPGA designs that allows a small board sporting a Xilinx Spartan 3 to add a 6502, a Z80, a 6809, or a PDP/11 to a BBC Micro via the tube interface. There’s something satisfying about a classic computer acting as an I/O slave to a fairly modern FPGA that implements an even older PDP/11.

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