Re: [stella] a $16 question...

Subject: Re: [stella] a $16 question...
From: Greg Troutman <mor@xxxxxxx>
Date: Fri, 30 Jan 1998 09:01:25 -0800
Chris Wilkson - MCD wrote:
> 
> > Maybe.  At any rate, 100 boards is enough interest for me to do the design.
> > The cost of a bare board shouldn't be terrible.  And I think I can get away
> > with only 2 chips...I'll hafta dig out my bank switching info to verify that.
> > At any rate, I'll have an estimate for a EPROM-less board by Monday...
> 
> The info I have doesn't say anything about initialization.  Is this handled
> by software?  Ie. are the last few bytes of each 4K page identical...same
> RESET/SWI vectors, etc?  (This is what I think)  Or does the cartridge always
> powerup to the same 4K page?

Random startup is not a big problem.  Besides the reset/swi vectors you
need to duplicate a bank-switch to get the game started:

	org $x000	
	sta $FFF9	;switch to main startup bank, in this case $F000

bankXcode:		;in $F000, this is the actual game startup routine
	...

	org $xFFC	;reset/swi vectors in case we start in this bank
	dc.w #$x000 
	dc.w #$x000

I think that's how it was actually done in Atari carts, but even if not
it should always work anyway through the magic of software ;)

--
mor@xxxxxxx
http://www.crl.com/~mor/

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