Task: Purchase and Install a PiStorm CPU Accelerator for Your Amiga 500 16-Bit Computer
Needed: Web Browser, PiStorm, Raspberry Pi 3A
Time: 30-60 minutes
Introduction
When I built my Amiga 500 my first task was to find a hard drive emulator. I have previously posted about the Gotek floppy disk drive emulator but really wanted an SD-card solution for emulating a hard disk. This led me to the PiStorm that is so much more than a hard disk solution. First and foremost, the PiStorm was developed as a CPU replacement and accelerator. This device replaces the 68000 CPU in the Amiga 500 and uses a Raspberry Pi to emulate multiple 680X0 CPUs including the 32-bit 68030. Further, it uses the onboard RAM of the Raspberry Pi to provide effectively limitless fast RAM that can be accessed at Pi speeds. This greatly expands the capabilities of the Amiga 500. On top of this, it can access software on the SD card and can communicate over WiFi.
Interestingly, multiple people have developed modern operating systems (OS) that run on the Raspberry Pi with full HDMI out. These OS flavors can be used to run some games in HD and launch software through the Amiga and its RGB video out. Thus, you can have a vintage game running on the Amiga with RGB display on one monitor and the modern OS running on a second HDMI display. Development of these new OS tools was made possible by a lightweight 680X0 emulator called Emu68 that was built specifically for the ARM processor in the Raspberry Pi. Popular packages or distros include Caffeine OS (free, see screenshot at end of post), Coffin OS (commercial), and AmiKit (commercial). The easiest way to get started preparing an SD card for booting the PiStorm is to use the Emu68 Imager. All you need to a copy of a Kickstart 3.X ROM and Workbench 3.X ADF files along with your SD card. Note that you need a license for the Amiga OS files available from Amiga Forever to legally use them. They also have the rights to a number of other software titles.
The following is instructions for purchasing and installing the PiStorm. Note that PiStorm is an open-source project.
Instructions
Before you purchase an onboard PiStorm, note that the two I received had round pins that would not fit in the standard 64-pin CPU socket in my Amiga 500 motherboard. I had to desolder the socket and solder in a new one with round holes. There are external versions you plug into the side expansion port that might be more convenient if you are not able to solder.
First, purchase a PiStorm. Fully assembled PiStorms are available on eBay for around $40 to $75. They are also available from several different online Amiga stores. These can be found through Google.
Second, purchase a Raspberry Pi 3A+. These are available on Amazon and from other sellers such as DigiPart for around $30 to $40. The PiStorm website suggests that a Raspberry Pi Zero 2 will also work and might be more available. I haven’t tried one of these.
Third, you will need a 64Mb or 128Mb micro-SD card for preparing the boot image. I went with the 128Mb model to make sure I had plenty of space. These cost around $15 at the moment. I detailed above in the intro how to image the card using the Emu68 imager with supplying your own Amiga OS software. This is what I did the first time. I later downloaded a Caffeine OS image and installed it using the Raspberry Pi imager. This also worked and provides the modern OS with HDMI out.
Fourth, as I mentioned above, I had to solder in a new round hole CPU socket to accommodate the round pins of the PiStorm. It would not fit in the stock socket that came with my Amiga 500 Rev 6A board.
Fifth, insert the PiStorm into the socket. Note the orientation with the black connector for the Raspberry Pi on the left and the notch facing the front of the Amiga.
Sixth, insert the Raspberry Pi 3A+ or Zero 2 into the PiStorm. Note the circuit board of the Pi will be facing down with the SD card slot visible facing up.
Seventh, insert the imaged SD card into the Pi and boot the Amiga. If you used the Emu68 imager with Amiga OS 3.X it should boot into the Workbench as shown below. If you used Caffeine OS, you should also connect your Pi to a second monitor as their will be some setup to do first with location and language, e.g.
That is it!
Comments
This is an amazing device with amazing software. I will do more posts later about using these modern OS packages and the ins and out of the PiStorm. There is SO much to learn and explore.
Here is the Sys Info benchmark test. Note the indication for a 68040 CPU running at many times the speed of the standard 680X0 CPUs found in the various Amiga models.
I use a switch to select which HDMI signal I want when using a single monitor.
Note that it is possible to direct 512K of slow RAM to give your Amiga 500 a full 1MB of chip RAM using the PiStorm. This Reddit post has more details.
Here is a screenshot of the Caffeine OS desktop captured from the HDMI signal from the Raspberry Pi. Yes, several emulators are included for Atari, Nintendo, c64, etc.
