SCN colour device driver for Spectrum Next and compatibles

 

The SCN driver is Copyright 2025 by Simon N Goodwin.

The latest is always at: http://simon.mooli.org.uk/QL/SCN

 

The SCN driver is released under the CC-BY-NC-SA version 4 License

(https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode)

 

SCN is a free QDOS colour display driver. It works like Sinclair’s SCR device, with many of the same SuperBASIC commands and 31 standard I/O TRAPs, but instead of output to a fixed-size 4 or 8 colour screen it drives 16 and 256 colour displays with configurable resolution and addressing.

 

SCN supports MODE256 - 256 colours at a resolution of 256x256 pixels - on all Spectrum Next hardware, including NGo and XBerryPi. The stipple patterns associated with ink, paper, border and strip colours 0..255 on Sinclair hardware now select solid colours.

 

1 – A MODE256 screen showing packed multicolour Minerva hexadecimal at the bottom and recolouring at 1 million pixels a second above that

2 This colourful animated pattern is generated from SuperBASIC using a MODE256 remix of Rod's colour patterns from the 1978 Apple 2 manual.

 

3 - Spectrum Next small founts can also be used on the Next QL

 

 

SCN can also be used to perform block operations (scrolling, panning etc) and to write characters to windows on 16-colour Next QL  displays, though small characters and odd window dimensions are not supported in MODE 16 since SCN always writes a byte at a time to display memory. 240 stipple patterns are available in MODE16, using adjacent pairs chosen from the 16 colours.

 

4 - As well as the usual Sinclair character sizes the SCN driver supports pixel adjustments to increase legibility or pack more onto the screen

 

Additional KS2 features

 

Spectrum Next hardware based on the Artix FPGA (currently the KS2 boards) has additional memory enabling it to support two more modes, MODE32 (256 colours at QL hiRes 512x256 pixel resolution) and MODE64 (65,536 colours). SCN fully supports MODE32 but does not directly support MODE64.

5 Sixteen text colours in MODE 16

The SCN driver comes with more than 5000 lines of 68000 assembly language source and SuperBASIC example procedures to test, profile and demonstrate its working. All the files can be freely downloaded from http://simon.mooli.org.uk/QL/SCN

6 - The RECOL256 keyword can also recolour 16-colour MODE 16 high resolution images via SuperBASIC to create an suitable remapping table