Trinity is an alternative firmware for the Olimex Neo6502 board: it builds on Paul Robson's official firmware and adds NeoDOS, a USB modem, new video modes and over 100 API functions.
Status In development · 0.16.71
Licence: MIT
The Neo6502 and its official firmware are the work of Olimex and Paul Robson. Trinity is a branch of that firmware: it starts from commit dc70908 (v1.0.0 plus 14 commits) on 18 September 2026 and keeps its MIT licence. The 153 functions of the official API remain available; 17 of them are modified.
Trinity adds NeoDOS as the working environment, a USB modem, new video modes, interrupts, a scheduler and a graphical toolbox.
To go back to the official firmware, copy its .uf2 file the same way: official firmware repository.
| Topic | Official firmware | Trinity 0.16.71 |
|---|---|---|
| Video modes | One mode: 320 × 240, 256 colours | Mode 0: 320 × 240, 256 colours; mode 1: 720 × 350 monochrome, 80 × 25 console; mode 2, trial: 320 × 240, 16 colours, two pages |
| At start-up | NeoBASIC | NeoDOS 0.32.1, A:\> prompt; boot/ start-up menu; NeoBASIC can be started from boot/ |
| Modem | Serial port on the UEXT connector | Pico W Wi-Fi modem plugged into USB-A (group 14); the serial functions can go through it |
| Interrupts | The firmware does not drive the 65C02 IRQ line | Interrupt tick from 1 to 1000 Hz and frame interrupt (60 Hz) |
| Scheduler | — | 4 round-robin tasks, semaphores (without NeoBASIC) |
| Toolbox | — | QuickDraw, events, windows, menus, controls, dialogs, resources (groups 32 to 38); Sierra AGI pictures (group 39) |
| Sound | 4 channels, 8 functions | 4 channels, 16 functions: per-channel and master volume, 8-bit PCM stream |
| API functions | 153 | 274, including 121 specific to Trinity and 17 modified official ones |
| Licence | MIT | MIT (AGI decoder under the EUPL 1.2) |
Official firmware: commit dc70908 (v1.0.0 + 14); Trinity: 0.16.71. Table updated on 3 October 2026.
Debugging the Neo6502 over SWD: a Pico W flashed with debugprobe, three wires (GP2, GP3, GND), OpenOCD, reading the running RP2040's memory, injected keystrokes, the core 0 rule — with photos of the bench. Read the article →