Howdy do. Some questions about this cute little timing counter I have
been made aware of.
According to the Stella manual, it says that the hex address determines
how many clock counts it takes for things to count down. But Bensema's
playfield document uses TIM64T and sets it for 44. If the number
automatically decrements every machine cycle, why not write 37 to
address $294 (TIM1T) to count down the number of scanlines? Or if I'm
thinking of the wrong cycles it needs to synch up with, write 111
(37*3) to address $294? What am I missing? Or is Bensema not using
the timer for counting the scanlines?
The timer is read at $284. How does it know which timer of the four
addresses to read? The way the computer works, wouldn't the numbers in
all four addresses start cycling down from whatever is in them at that
random moment when the Atari starts up?
"It holds 0 for one interval, then flips to $FF and decrements once
each clock cycle...to allow the programmer to determine how long ago
the timer zeroed out...." What happens if it hits zero again? It
starts at $FF again or it freezes at 0?
_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at http://mail.yahoo.com
--
Archives (includes files) at http://www.biglist.com/lists/stella/archives/
Unsub & more at http://www.biglist.com/lists/stella/
