Re: DHGR Video Riddle Solved!!!

[david@uow.edu.au (David Wilson)]

Matt Jenkins <mdj@bilby.cs.rmit.edu.au> writes:
>In comp.sys.apple2 Jeff Blakeney <CUTblakeney@home.com> wrote:
>> By the way, I'm only aware of one DHR mode.  560x192.  The number of
>> colours you get depends on whether you view it on a colour or
>> monochrome monitor.  If viewed on a colour monitor, you will get 16
>> colours but if you view it on a monochrome monitor, those 16 colours
>> appear as different dot patterns and you can see all 560 horizontal
>> dots.

>That's not correct. There is indeed *two* modes of DHR, 560x192 BW and
>140x192 16 color. Whether a byte in the video area is interpreted as
>color pixels or BW pixels is dependant on the high order bit of that byte.

But only if you have an RGB card. If you use composite video on a //e bit 7
is ignored in DHR mode.
--
David Wilson  School of IT & CS, Uni of Wollongong, Australia