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.
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 https://www.kilgus.net/ql/mister/
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.