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Can I use a simple EEPROM for a cartridge?


2 replies to this topic

#1 cbmeeks OFFLINE  

cbmeeks

    Moonsweeper

  • 323 posts
  • Location:Hixson, TN

Posted Wed Dec 19, 2018 3:00 PM

Lets say I have a stack of 8K and 32K EEPROMS.

If I match the pinouts, can I make my own CV carts or do I need some other logic in between?

Which brings me to my second question, how are /8000, /A000, etc. used on the CV? Would my cartridge have to set those somehow like with pull up/down resistors?

Im learning more about the CV hardware so please excuse my ignorance.

Thanks.

#2 ChildOfCv OFFLINE  

ChildOfCv

    Star Raider

  • 81 posts

Posted Thu Dec 20, 2018 6:21 PM

/8000 through /E000 are individually-decoded addresses representing A15-A13.  If any of them are on, that means A15 is high.  A14 and A13 decode as one of the other lines.  So if you were to use a single 32K EEPROM, it needs to activate based on ANY of those select lines going low.



#3 ChildOfCv OFFLINE  

ChildOfCv

    Star Raider

  • 81 posts

Posted Fri Dec 21, 2018 2:52 AM

And to answer your first question, you can connect the data and address lines directly.  Only chip select needs special logic to go active when one of those 4 decoded lines goes active (low).






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