It is currently Sun Aug 25, 2019 9:31 pm

All times are UTC - 7 hours



Forum rules





Post new topic Reply to topic  [ 5 posts ] 
Author Message
 Post subject: SNES cart with RAM banks
PostPosted: Thu Aug 15, 2019 11:31 pm 
Offline

Joined: Tue Feb 07, 2017 2:03 am
Posts: 750
Is it possible to make a SNES cart that has RAM mapped to the ROM banks, HiROM style. This way you can get FAST RAM, and put code into RAM? Or does the SNES force R/W to R when asserting /CART ?


Top
 Profile  
 
PostPosted: Thu Aug 15, 2019 11:41 pm 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 8539
Location: Seattle
/CART (or /ROMSEL, whatever you want to call it) is just a function of A23-A17 and A15.

"LoROM" games with RAM in bank $70 can access their RAM at 3.6MHz (in bank $F0)


Top
 Profile  
 
PostPosted: Fri Aug 16, 2019 2:29 am 
Offline

Joined: Tue Feb 07, 2017 2:03 am
Posts: 750
yes but that is the SRAM which is broken up into small chunks. I'm not talking about making SRAM but putting RAM banks as in whole 64K bank at for arguments sake E0:0000-E0:FFFF.


Top
 Profile  
 
PostPosted: Fri Aug 16, 2019 10:21 am 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 8539
Location: Seattle
I mean, the anecdote is just pointing out that you can already get it on existing hardware, just not "Very Large" RAM. But "Very Large" RAM is extremely rare on contemporary hardware regardless of PCB, so it's not much of a constraint.

The /RD and /WR strobes don't do anything funny based on address, other than the funniness during DMA.


Top
 Profile  
 
PostPosted: Fri Aug 16, 2019 12:38 pm 
Offline

Joined: Sat Apr 25, 2015 1:47 pm
Posts: 435
Location: FL
Oziphantom wrote:
Is it possible to make a SNES cart that has RAM mapped to the ROM banks, HiROM style. This way you can get FAST RAM, and put code into RAM? Or does the SNES force R/W to R when asserting /CART ?

Believe it or not, Nintendo did it already!


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: No registered users and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group