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flashjazzcat

Member Since 23 Nov 2008
ONLINE Last Active Today, 10:56 PM

Posts I've Made

In Topic: Conditioning 5V TTL CSYNC signal to ~1V for SCART

Yesterday, 4:20 PM

Can you not pick sync directly from pin 15 of CD4050 for a start instead of deriving it from composite video? Applying a voltage divider to that produced good results when I tried it.

In Topic: ATARI 800 was the first computer in 1979 with native Y/C output

Yesterday, 3:16 PM

I'm concerned I misquoted him now: can't recall for sure whether he was reviewing the Vic 20 or the C64.

In Topic: How to Type/print Upper/Lower text

Yesterday, 2:51 PM

So I can run code that is written to take advantage of it. Properly written 6502 code runs perfectly on it and on Antonia, and the other 816 upgrades.


Best solution I can suggest there is to vote with your feet and simply not attempt to run code which won't run on your CPU. There will be two reasons for the use of illegals: necessity or arrogance. If it's the former, there's not much you can do about it, and if it's the latter, who wants to run their software anyway? :)

I suppose a third reason would be ignorance, but you'll quickly see from the reaction of the software's author which is the case.

In Topic: Load Data from disk in Assembly

Yesterday, 2:46 PM

The Player multiplexer DLIs have no WSYNC in them because they just set HPOSP#, SIZEP#, and COLPM# and usually does not need to sync with the horizontal line. Usually not an issue at 1.79 mhz, because the CPU are loaded before writing to any Antic/GTIA registers and the beam has moved passed the right side of the screen. But at higher speeds, the beam may be still one line up on part of the line, so some pixels may flicker on occasion.
 
The other issue at the bottom is sprites may not extend below as far below the playfield for overscan effects because the last DLI calls for erase before redrawing new sprites.


This illustrates my point exactly. You are relying on the properties of the CPU frequency to govern the timing of graphical effects. The simple expedient of syncing with the current scanline will likely allow your display to work perfectly well regardless of CPU frequency. Taking these steps during the initial coding phase saves the effort of retroactively fixing things later on.

In Topic: Ben Hecks latest portable A8 build

Yesterday, 1:59 PM

I'm glad somebody noticed the grammatical typo. I posted the title quickly from my phone that day. Can admin edit the title please to add the apostrophe :)


An impeccable reaction, if I may say. Many don't react so well. :)