Re: Q: Timing: How many clock-cycles to print one char on screen?

[david@uow.edu.au (David Wilson)]

Holger Picker <pickerh@uni-muenster.de> writes:
>Ah, I didn't know that (never heard of it)! What does it mean to the processor? Would it 
>mean that after 65 clock-cycles the processor does one/two (complete) wait-cycle? Or is the 
>difference too small to be noticeable (hearable? What about processor loops that access 
>$c030? Could you hear a "background-humming"?) I've always thought that the 6502 in an 
>AppleII runs at constant speed. Now it seems it was only true for PAL-Apples.

I seem to recall reading somewhere that the stretched cycle is audible in
a speaker loop - the main frequency is supersonic but the streched cycles
introduce an audible component to the mix. I will have to see if I can find
the reference.

David Empson wrote:
>I live in New Zealand, and I ordered my copy of Understanding the IIe
>from Byte Works.  They posted it to me, but I don't remember whether it
>was airmail (quite expensive) or surface - the latter is more likely.
>(This book is a softback, about 8.5 by 11 by 1 inch, or 215 x 280 x 25
>mm.)

I live in Australia and got my copy from Tom Weishaar (sp?) at
Open Apple magazine. I think I got Understanding the Apple ][
from Byteworks.

Speaking of Understanding the Apple IIe - has anyone tried the program listings?

I just tried Figure 8-20 (page 8-45) "LORES80 CONCENTRIC CIRCLES" and it
doesn't work on my //e. It fails to clear the text region of a mixed
graphic screen properly (the alternate columns are left with junk in them)
and the blocks that make up the circles are not drawn after a couple are
displayed.
--
David Wilson  School of IT & CS, Uni of Wollongong, Australia