29-07-2022, 10:01 AM
G'day Under4Mhz
The Microbee Premium series & 256TC has the extra PCG memory.
Normally these machines were supplied with 8 banks of PCG memory which was enough
to have a full 64 x 16 character screen (resolution 512 x 256) without running out of
PCG characters. The Premium series machines are reasonably common but there are still
more of the 'Standard' (Non-Premium) machines out there. The 256TC is pretty rare
as they didn't sell particularly well.
The Premium & 256TC also has the 'Viatel' option fitted as standard which would allow
32 / 40 column mode. This option halves the video dot clock rate so that 80 columns
becomes 40 columns.
Have a look at the Microbee Technical Manual in the repository for details on how to access
the extra PCG banks in the Premium series.
The Microbee Premium series & 256TC has the extra PCG memory.
Normally these machines were supplied with 8 banks of PCG memory which was enough
to have a full 64 x 16 character screen (resolution 512 x 256) without running out of
PCG characters. The Premium series machines are reasonably common but there are still
more of the 'Standard' (Non-Premium) machines out there. The 256TC is pretty rare
as they didn't sell particularly well.
The Premium & 256TC also has the 'Viatel' option fitted as standard which would allow
32 / 40 column mode. This option halves the video dot clock rate so that 80 columns
becomes 40 columns.
Have a look at the Microbee Technical Manual in the repository for details on how to access
the extra PCG banks in the Premium series.