[stella] 2600 questions
Subject: [stella] 2600 questions|
From: Glenn Saunders <cybpunks@xxxxxxxxxxxxx>
Date: Tue, 20 Jun 2000 16:35:19 -0700
From the 2600 programmer's guide:
"Since the TIA latches all instructions until altered by another write
operation it could be updated every 2 or 3 lines".
I'm assuming this means that whenever you want the same scanline to show up
for multiple scanlines, you simply execute a WSYNC on the successive
lines? But for any kernel that does register hits in mid-scanline, you
must re-execute those hits on every scanline, right?
So if you just wanted to draw a stripe, you could have one line in the
kernel and all others would be WSYNCs? Could the programmer also use this
screentime to perform number crunching and other non-visible stuff? This
is how the paddles are typically read, correct?
"when a 1 is written to D1 of the CTRLPF register, the left half of the
playfield takes on the color of player 0 and the right half takes on the
color of player 1."
Does this mean it actually does a color shift automatically in
hardware? Also, this feature does not prevent sprites from being used on
those scanlines, does it?
That's one feature I never knew about. I thought Combat was doing the
color shift manually.
Also, has anyone thought of trying to wire something into the unused bits
(D5 D4 and D2) of PortB/SWCHB?
Also, anyone know the reason why the trigger buttons connect to the TIA
instead of PIA?
Glenn Saunders - Producer - Cyberpunks Entertainment
Personal homepage: http://www.geocities.com/Hollywood/1698
Cyberpunks Entertainment: http://cyberpunks.uni.cc
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