About 14.07.2019
Programming the Pi
The original intend was (and actually still is) – to use a standard OS on the pi, connect the Vectrex and be able to run programs on the pi that display well on the Vectrex.
This more or less works. The thing is only “more or less”. Vector drawing functions on the Vectrex must be very VERY exact when timing is concerned. You can see a difference of less the 1 micro second.
Every “standard” OS uses interrupts. These interrupts take usually way longer than 1 micro second. So running vector output on the Vectrex always has some disturbences, when running from a pi OS.
Kevin did extensive research and experiments with different OS. Graham tried newer Pi generations (non Zero) with multiple cores (and exclusive cores for Vectrex communication)…
As I understand it – all to no avail… the display is disturbed.
That is the reason one of my first “huge” undertakings was to try a bare metal approach (no OS, but using the pi exclusively).
On the very first day I got my personal PiTrex working I took following video:
Ignore the “text” – but see the “disturbances”… in between… They don’t look like much – but in a finished product you would not want to have them…