Recreating the Commodore PET with an FPGA

commodore_pet_fpga_clone

[Thomas’] love affair with Commodore computers spans well over 30 years, and not too long ago he decided to recreate one of his favorite Commodore offerings, the PET. As we have seen with similar undertakings, this sort of project is no easy task, but [Thomas] seems to be making his way along nicely.

Using a Xilinx Spartan-6 FPGA on the Digilent Nexys3 dev board, he has implemented the Pet in Verilog. Like the original, his clone contains 16K of both ROM and RAM, utilizing the same simulated 6502 microprocessor he used on a previous Apple ][+ project. The FPGA version of the computer sports a 640×400 resolution which is twice that of the original, so [Thomas] simply doubled the size of each of the PET’s pixels to fill in the extra space.

[Thomas] has made some great progress so far, including the ability to load games and other programs from cassette images over a serial connection. He says that there are still a few loose ends to tie up, but it all looks good from here!

Continue reading to see a short video of Space Invaders running on he PET recreation.

Continue reading “Recreating the Commodore PET with an FPGA”

Going a long way for Game Boy Advanced video out

Here’s an intense hack that lets [Matt Evans] play Game Boy Advanced on a larger LCD monitor. He didn’t take the easy way out during any step of the process.

He’s using an FPGA to translate the LCD signals from the GBA hardware into a 1280×960 picture that is then pushed to the large monitor. But did he use an FPGA development board? No, instead he picked up an old PCI card at a surplus store because it had a Xilinx Virtex-E FPGA. So the first thing he had to do there was to remove unneeded components and figure out how to make the connections to reprogram that chip.

So next you’d grab a working monitor and hook it up to the FPGA signal, right? Wrong, [Matt] had a slightly borked monitor, getting rid of the LVDS section and wiring up his own connections to push the RGB signals through in parallel.

Yeah, that’s a lot of work. But as you can see in the clip after the break, it works like a charm. If you’re looking for some other gnarly video-out hacks, check out this one that lets you play Game Boy on an oscilloscope.

Continue reading “Going a long way for Game Boy Advanced video out”

FPGA Arduino shield uses Kickstarter as a preorder system

[ Jack Gassett] is working on an FPGA shield for the Arduino. At first the idea of this expansion board seemed a little silly. But [Jack] mentions that the FPGA board can be quite useful for adding higher-order electronic complexity like HDMI capabilities to an Arduino. We’re not totally sold on the idea, but he’s not making the board solely for use with an Arduino either.

The plan is to use a Xilinx Spartan 3A FPGA which comes in a ball-grid array package. And that is the reason [Jack] decided to use Kickstarter for this project. He shared some of his issues with BGA components in a home manufacturing process a while back. To get these working reliably you need to have them professionally assembled, and that requires a sizable upfront investment. But as we read through his proposal it struck us that he’s actually using Kickstarter as a preorder system. You can get a base model with just the FPGA soldered on the board for $55. Not bad considering the chip will cost you at least $20 without assembly. Each level up includes a few more components like SRAM or add-on PCBs.

We get a lot of tips pointing to Kickstarter proposals but this is one of the few that seems right on the mark for supporting open and innovative development. Great work [Jack]!

[Thanks Simon]

Simulating VHDL of an AVR8 soft processor

Okay, now we’re beginning to feel a bit like [Alice]. This tutorial shows you how to simulate VHDL code. This code is intended to run on an FPGA and includes a software-only version of the AVR 8-bit microcontroller core. Essentially, you’ll simulate VHDL code that simulates AVR hardware. Wrap your mind around that!

The code is intended to run on a Papilio Field Programmable Gate Array development board. We saw an early version of this board running the AVR8 core about a year ago. However, you don’t need to have any hardware to follow along and recreate this simulation yourself. It might be a great way to get your feet wet with FPGA programming before making that first hardware buy. Five different screencasts take you through the process of getting the AVR8 code, using an altered Arduino IDE for it, setting up a free version of Xilinx ISE to run the simulation, then setting it free and interpreting the data that the simulator spits out the other end.

V4Z80P: The 8-bit laptop

[Phil] over at Retroleum has cobbled together a clean, well put together laptop based entirely around a Zilog Z80 microprocessor and a pair of Spartan II FPGAs. These FPGAs allow him to reduce the number of devices on his board, and therefore cut his production cost as well as device size. He even managed to integrate a salvaged PSOne screen. The laptop comes complete with [Phil]’s own Homebrew OS as well as a great graphical vector based demo.

Sure he’s updated the project in recent years to shrink the board, speeding up the Z80, and increasing the peripheral speed and functionality, but we’re suckers here for a total package hack. Seriously though, check out the newest version of the device as well as the backlog that shows the project growing over time.

Thanks to [Steth] for the heads up.

Tiny Cray-1 courtesy of an FPGA

[Chris Fenton] spent a year and a half constructing a 1/10th scale Cray-1 reproduction. The famous supercomputer was meticulously modelled in a field programmable gate array for a “nearly cycle-accurate” reproduction. [Chris’] hardware of choice for the project is a Xilinx Spartan-3E 1600 development board, using 75-80% of the available resources. The finished product runs at 33 MHz and is missing a few functions but it sounds like they don’t affect code execution. We like that he didn’t stop with the processor implementation, but also took the time to produce a case for the development board that looks just like the original.

Unlike the Atari 2600 FPGA project, we’re not quite sure what we’d use this for. But that doesn’t diminish the excellence of his work.

T-Mobile G1 teardown

g1teardown

In our Dev Phone 1 excitement last week, we somehow overlooked phoneWreck’s teardown of the T-Mobile G1. The complex slider mechanism is certainly worth looking out. One of the major oddities they point out is the inclusion of two vibration motors. One is mounted next to the SIM on the mainboard. While the other is mounted in the frame next to the earpiece. We wonder what was gained/solved by using two. The phone also includes a digital compass module. We’d like a more detailed explanation of how the Xilinx CPLD is used. From this article in 2006, it seems HTC uses them to generate custom clock signals and switching off devices for power management.