Welcome aboard!
A few wiggles of the coreboard connectors is often enough to coax a microbee working again.
Also, it is usual that the keyboard contacts have died and require retreads or replacement.
To find out more, someone would love to have a closer inspection of the unit.
As a guess from the photos it's an OKI MSM5823 RTC connected via the 8255 PPI.
Interestingly enough the same was done with a prototype Microbee Floppy Disk Controller that didn't make it to market;
it too had an RTC connected via a 8255 PPI, a baud rate generator and a dual port UART for "Real" RS-232 Ports.
The piggyback board looks like an expansion of the CHAR, ATTR and COLOUR RAM to accomplish more video functionality from different screen configurations.
Have a look at the Doppelganger posts to see what's possible from the Games front.
A few wiggles of the coreboard connectors is often enough to coax a microbee working again.
Also, it is usual that the keyboard contacts have died and require retreads or replacement.
To find out more, someone would love to have a closer inspection of the unit.
As a guess from the photos it's an OKI MSM5823 RTC connected via the 8255 PPI.
Interestingly enough the same was done with a prototype Microbee Floppy Disk Controller that didn't make it to market;
it too had an RTC connected via a 8255 PPI, a baud rate generator and a dual port UART for "Real" RS-232 Ports.
The piggyback board looks like an expansion of the CHAR, ATTR and COLOUR RAM to accomplish more video functionality from different screen configurations.
Have a look at the Doppelganger posts to see what's possible from the Games front.