[sebhc] Graphics Card

Barry Watzman Watzman at neo.rr.com
Tue May 15 11:15:36 CDT 2007

Heath seriously investigated offering a full graphics version of the H-19
terminal (would presumably have worked with the H89 as well), but we did not
pursue it (kind of over my objections).  There was an outside 3rd party
design firm in Calif. that wanted to do it, and I felt that the costs were
reasonable, but the rest of management felt that the cost was too high and
the market too small.


Barry Watzman

Watzman at neo.rr.com




From: sebhc-bounces at sebhc.org [mailto:sebhc-bounces at sebhc.org] On Behalf Of
ziloo ...
Sent: Tuesday, May 15, 2007 11:30 AM
To: sebhc at sebhc.org
Subject: [sebhc] Graphics Card


When collecting bite and pieces of information about H-89 on the net, I came
this note from some folks:

"The base H-89 had no graphic modes, just 33 graphic characters. At least
two different
add-on boards were created that gave the H-89 bitmapped graphics
capabilities, but 
I'm pretty sure they both required hardware modifications to tie them in to
terminal board - this was not a simple plug-in expansion card." ...


"There's a 3rd party graphics board fitted on top of the CRT (seriously). 
It links into the PSU/video cableform from the Terminal logic board to
the monitor, and also into 8 of the RAM chip sockets on the CPU board.
The RAMs you pull to plug in the cables go into the graphics board, 
which contains another 16K of RAM as a bitmapped display buffer." ...


"OK, the manual says 'Micronex Pixelplotter Graphics on the Z89/RFI 
computer'. It also says 'Micronex Limited, Harford Square, Chew Magna, 
Bristol, England'. I've got the installation instructions and memory maps.
The thing contains 16K of RAM which is bank-switched with 16K of the 
normal memory. I think my board uses port F2H, bit 3 to select the new 
16K, but I'm not absolutely sure." ...

Has any of our SEBHC folks been familiar with any graphics add-on
feature for H-89 system?




oredsearch_v9.php?o=US2226&cmp=Yahoo&ctv=AprNI&s=Y&s2=EM&b=50>  customers
who are looking for what you sell. 

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