Hello,
What if NTSC monitor and television become obsolete? The
manufacturer
stops making NTSC. It is going to replace HDTV. How can we overcome
NTSC
problem? The answer is to use VGA monitor.
We have enough information what we use schematic for Apple //e's
motherboard. We should be able to redesign Apple //e's motherboard.
NTSC
circuit will be removed to replace VGA circuit. Apple II 8-bit slots can
be
replaced to PCI slots. 16MB RAM will be built in motherboard. It is to
be
658C16 MPU.
Video RAM will be located higher RAM above $E0 bank. $400-$BFF for
TEXT
and $2000-$5FFF for GRAPHIC ceases to exist and they will never be
directed
to video. We may use special routines to read video data from $400-$BFF
for
TEXT and $2000-$5FFF for GRAHPIC before they are translated to video RAM
in
$E0 bank. Games in 658C16 code can be written to fill the RAM memory
from
$200 through $FFFF as long. Softswitches on $C000 through $CFFF will be
moved to higher RAM like $FF bank. It has special switch to use
softswitches in $0/$1 bank for compatibility with Apple II.
We can change the 14M crystal oscilloscope chip to 28M crystal
oscilloscope. We know that NTSC has 15.7K horizontal freq and 60Hz
vertical
freq (262.5 * 60Hz). We want 640x480 resolution. We are going to have
31.4K horizontal freq and 60Hz vertical freq.
28M crystal oscilloscope chip can cause 658C16 MPU to be 2 MHz and
RAM
to be 4 MHz. It is a problem. I have a good understanding of timing
generator in HAL16R8 chip. I should be able to modify timing generator
to
run 1 MHz on 658C16 MPU and 2 MHz on RAM.
We need to have a good understanding how VGA monitor work first.
What
do you suggest with my idea?
Bryan Parkoff