Re: Apple //e's RGB Card To Apple IIgs' RGB Monitor

["mdj" <mdj.mdj@gmail.com>]

Michael J. Mahon wrote:

> I'd suggest using three 4-resistor networks to do the three 4-bit D-to-A
> conversions--four resistors beats a D/A chip for just 4 bits.

Agreed. It might also be possible nowadays to use a uC to replace the
GAL idea. GAL/PAL seems to be going the way of the dodo, and using one
small cheap chip instead of two seems a good move.

> And buffer amplifiers may be needed for the RGB signals as well, if the
> RGB monitor's inputs are 75 Ohm.

Without this, you'd see some pretty strange colour artifacting.

Also Bryan - your table seems to be quite wrong. Care to post a
corrected one?

Have you done a comparison of the IIgs's colour palette to the actual
composite colours? It's possible that 12 bit RGB only provides an
approximate of some of the colours, although admitedly it's probably
close enough.

Matt