Development Resources for Psion Software and Hardware

Psion Community (psion.community) collects the main development resources for classic Psion machines in one place: a documentation archive, the SIBO C SDK bundled with the TopSpeed C Compiler, the CTRAN preprocessor, an OPL Language Server, and source code hosted on Codeberg. These cover both EPOC16 (SIBO) and EPOC32 development, so what you use depends on whether you are targeting an Organiser II, a Series 3, or a later Series 5/netBook-era device.

Documentation

The site links a collection of Psion-related documentation as the starting point for development work. This is the reference material to consult before writing code, since the platform APIs and toolchain behaviour differ significantly between the 16-bit SIBO line and the 32-bit EPOC devices.

SDK and Compilers

SIBO C SDK

The SIBO C SDK is packaged together with the TopSpeed C Compiler. This is the toolchain for EPOC16 development — the platform used by the Organiser II and Series 3 family. If you want to write native C for those machines, this is the package to look for.

CTRAN

CTRAN is described as a modern SIBO object-oriented C preprocessor. It sits in front of the C toolchain to add object-oriented constructs to SIBO C, which is useful when you want more structure than plain C offers but are still targeting the original 16-bit environment.

OPL Language Server

The OPL Language Server supports OPL, Psion's built-in programming language. A language server typically provides editor features such as diagnostics and completion, so this is aimed at people writing OPL rather than native C — a lower-friction route if you are building applications rather than system-level code.

Source Code and Collaboration

Codeberg hosts the source code for the psion.community website itself along with other Psion-related software. The site states it welcomes contributions on Codeberg, so this is also the place to submit fixes or new material rather than only to download existing projects.

Choosing a Starting Point

If you are new to the platform, start with the documentation to identify your target device's OS generation, then pick the toolchain that matches it — the SIBO C SDK for EPOC16 machines, or the EPOC32-era resources for Series 5 and later.