Psion Series 3a with custom green case. I think of it as looking like dragon skin.

Near the end of last year I hit a wall. After spending months trying to learn VHDL and feeling very much like I was failing, I decided to put my participation in the project on hold. I had burnt out and it was time to walk away, if only for a little while.

UPDATE: The latest version of SIBODUMP has just been released along with binaries for Windows and macOS. Take a look here: https://codeberg.org/thelastpsion/sibo-ssd-dump

SIBODUMP and its partner sketch Dump.ino have slowly developed into a very handy toolkit for SSD ripping. In its current form it’s able to dump blocks from any ASIC5-compatible SSD (so that’s all of them). I’ve also started to get it to pull images in native ASIC4 mode - all but the very earliest SSDs have ASIC4, and being able to talk using ASIC4’s registers could open the doors to even more development.

To go with siboimg, there’s now sibodump! This is a tool of two parts: first an Arduino sketch which talks to the SSD using SIBO-SP, and a C app that controls the sketch over serial and dumps the image to a file. The app runs on Win32 and Win64, Linux and macOS. It should run on *BSD, but I haven’t tested it yet. You’ll also find some binaries for Win32, Win64 and macOS in the repository.

A month ago I had never typed a line of C. Concepts like pointers, structs and treating variables as actual blocks of memory rather than abstract values were alien to me. But I really wanted to get into C; I knew that knowing the language would be vital for this project and there was only so long that I could put off learning it. I needed a target.

Karl had already written a Windows app in C# that would extract files from an image of an SSD. The Flash format had been well documented by the fantastic Clive D W Feather in his invaluable collection of SIBO documentation known as The Psionics Files. So I decided to follow in Karl’s footsteps and write an SSD file extractor in C. Something that would be more portable than his C# app, that I could compile on Linux, *BSD, macOS and Windows. And so, armed with a copy of the second edition of K&R and a few pre-ripped SSD images, my journey began.

Ever since the start of this project, the SIBO Serial Protocol (SIBO-SP) has loomed large as Something We Need To Know About. It’s a protocol using 12-bit packets, a LSB-first data payload, and a series of reset and select control commands, all done on one data wire and one clock wire. As you’ll see in previous logs, we’ve managed to decode a large amount of it and I’ve published my Sigrok decoder on my GitHub page.