ELI5 - Pokey Divisor Zero

[Atari8guy]

I don't get it, (not that I'm a hardware or software guy at all) but if you divide anything by zero, don't you poke a hole is space/time?  So, if anyone is willing, could you explain like I'm a 5 year old, how the transfer rates work, why pokey divisor zero seems to be the fastest and what is it fastest compared too?

[foft]

It takes something like 7 cycles to reset a timer. So need to add that to the divisor.

 

So its: clock speed/(divisor+7)/2.

 

1780000/(40+7)/2 =~ 19k

1780000/(0+7)/2 =~ 127k

Edited August 31, 2020 by foft

[Atari8guy]

Thanks for that.  Any book recommendations where I can learn more?

Edited September 8, 2020 by 8bitguy1
first edit read too sassy, no sass intended

[foft]

This one is fantastic

http://www.virtualdub.org/downloads/Altirra Hardware Reference Manual.pdf

Take a look at that and if its too complex then someone may be able to suggest others.

 

Another great one:

https://www.atariarchives.org/dere/

[ivop]

20 minutes ago, 8bitguy1 said:

Thanks for that.  Any book recommendations where I can learn more?

 

Altirra Hardware Reference Manual

 

And De Re Atari, Mapping The Atari, stuff like Atari 800XL Service Manual, and the datasheets.