SuperCharger Control Register Question

[Delicon]

Is it possible to read back the current control register value? If not, how do you maintain the bank configuration when you want to enable and disable writing?

 

Thanks,

 

Vern

[mos6507]

I think this has been answered with a no. I checked Suicide Mission and it is reserving a separate RAM address (looks like $80, same as the loader uses) to keep track of bank config.

[supercat]

I think this has been answered with a no. I checked Suicide Mission and it is reserving a separate RAM address (looks like $80, same as the loader uses) to keep track of bank config.

 

If you don't mind using a byte of ZPRAM (well, five bits of it anyway--if you wanted you could stuff flags and things in the upper bits), you may find it useful to set address $81 to $10. Then you can use CMP ($80),y to switch modes. My own tendency is to mask out everything but the write-delay bits (does anyone know, in hardware terms, what they do?) and just use LDY #desiredvalue, but you may use other approaches.

[Delicon]

(does anyone know, in hardware terms, what they do?)

 

Just a guess without being there when they designed the cart, but I would bet these bits add wait states when for ROM and/or RAM access. This makes sense if they were planing to shift providers for their RAM/ROM, maybe in the future thinking they could save money with different brands.

 

Vern

Edited October 17, 2006 by Delicon