Monthly Archives: April 2020

SCRXLIM and SCRYLIM extensions

SCRXLIM and SCRYLIM are two functions which return the screen width and height respectively on high resolution systems, or the outline width and height if used with secondary channel numbers. May be linked to compiled programs and included with free or commercial programs as required. They are freeware, and were written as compact extensions for use when larger toolkits which include similar functions are not required.

Download from

MiSTer Update

Busy chap that he likes to be, Marcel Kilgus has improved the QL core of the MiSTer system.

MiSTer is an open project that aims to recreate various classic computers, game consoles and arcade machines, using modern hardware. It allows software and game images to run as they would on original hardware, using peripherals such as mice, keyboards, joysticks and other game controllers. MiSTer utilizes a readily available FPGA board called the ‘DE10-Nano’, which connects to your TV or monitor via HDMI video out. It can additionally be expanded with various add-ons (such as a USB hub, SDRAM, audio and VGA out).

Marcel felt that as the QL is not as popular as other platforms so the core was still only a pretty basic port of the original MiST board, so in 2018 he worked on updating the core, to include a “Gold Card” implementation and a special version of SMSQ/E, plus a QL-SD implementation which runs correctly at all CPU speeds through switching the 68k core to the fx68k core. The software packages can be downloaded from Marcel’s website at


One of the challenges QL users currently face is the lack of monitors able to correctly show the QL display. The RGB output from the QL is not fully suitable for connection to modern flat screen monitors.

Some users have had a limited success with SCART to HDMI video upscalers. But as VGA computer monitors have been so common and readily available, we have long dreamed of being able to attach a QL to such a monitor. Oh, and make sure that our display monitors correctly display the full 85 character/512 pixel QL display without losing a couple of characters at the left and right edge.

After his foray into the QL hardware world with his work on updating the QL-SD interface to work with Gold Cards etc, Marcel Kilgus is now working on a small QL-VGA board to allow QLs to be successfully connected to modern monitors.

Marcel’s solution consists of a Cyclone II development board with an FPGA and other components, to which Marcel has added a second small board with RGP input with level shifter, VGA output and SRAM chip. The FPGA chip is programmed to do the hard work on the video – Marcel says it empowers software people like him to solve real hardware problems.

The idea behind the board, put simply, is that it converts the 512×256 50Hz QL screen into a standard 1024×768 60Hz VGA signal that can be processed by probably every monitor in existence, or further converted by additional hardware to HDMI if need be.

QL-VGA pictures from Marcel Kilgus

The device is currently undergoing testing before there can be a production run, so availability date and price are unknown at the time of writing.

Keep up to date with this by following Marcel Kilgus’s blog at