[Coco] auto-starting game paks

Roger Taylor operator at coco3.com
Tue Jan 20 21:24:17 EST 2009


At 05:21 PM 1/20/2009, you wrote:
>Roger,
>
>Sorry about the humor. Hard to tell when you are asking a serious 
>question, joking or just answering your own questions?????.

I know, and sometimes I'm in a hurry and after I hit the Send button 
I realize that it sounded like a newbie came in and asked, What's a CoCo?  :)


>You can control the CPU to have it do what ever you want it to do, 
>via software and or hardware.

I've never known the CoCo to jump-by-hardware to $C000 if CART is 
active the instant the CoCo comes on, so I had to ask.


>CPU to be told the first address to start running code from? Yes

Ah ha.  I wonder if *some* vintie computers actually decide where to 
jump based on whether a cart is plugged in.  Seems logical to me.  It 
would probably cure the problem of an auto-starting pak continously 
executing the first instruction if the interrupts-to-CPU aren't 
configured correctly from the cartridge software.


>Certainly the CPU can be forced to jump to $C000 if something on the
>motherboard wanted to do that, no?
>
>Yes, ROMs. Color Basic and Extended Color Basic.

It's not that important, but I was trying to figure out a way to 
auto-start a 6551-based cartridge that quickly after starting uses 
the same CART signal for another purpose.  Ah, the ideas.  When do 
they end.  :)

-- 
Roger Taylor

http://www.wordofthedayonline.com




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