It is currently Fri Feb 15, 2019 3:47 pm

All times are UTC - 7 hours





Post new topic Reply to topic  [ 21 posts ]  Go to page Previous  1, 2
Author Message
 Post subject: Re: Switching ROM banks
PostPosted: Sat Feb 09, 2019 3:37 pm 
Offline

Joined: Mon Feb 04, 2019 8:47 am
Posts: 8
Quote:
I'm not certain. If I had to guess, I suppose you reversed things twice there.

Yep, that was what the error was boiling down to!

I got things working now! Wohoo!

However, I got two cartridges that I can test, one with a MBC3(GB game) and a MBC5(GBC game) and currently it only works with the GB game that has a MBC3. http://gbdev.gg8.se/wiki/articles/Memory_Bank_Controllers#3000-3FFF_-_High_bit_of_ROM_Bank_Number_.28Write_Only.29 say that
Quote:
3000-3FFF - High bit of ROM Bank Number (Write Only)

The 9th bit of the ROM bank number goes here.
Is the reason it doesn't work because I don't write the 9th bit? And would writing the 9th bit be done the same way as in step 2 and 3 (from the section: Now I will explain how to switch ROM banks!) before setting wr low ?

Thanks!


Top
 Profile  
 
 Post subject: Re: Switching ROM banks
PostPosted: Sat Feb 09, 2019 4:16 pm 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 8130
Location: Seattle
The 9th bit ought to only matter if you're dealing with a game that is larger than 256 (8 bits) × 16384 bytes = 4 MB.


Top
 Profile  
 
 Post subject: Re: Switching ROM banks
PostPosted: Mon Feb 11, 2019 6:48 am 
Offline

Joined: Mon Feb 04, 2019 8:47 am
Posts: 8
Makes sense!

What I don't understand then is why the Game Boy game switches rom bank just fine, but the Game Boy color game won't change it's rom bank... (I tried to switch to all the available rom banks, but it won't switch from the default one)

Any ideas ? :?


Top
 Profile  
 
 Post subject: Re: Switching ROM banks
PostPosted: Mon Feb 11, 2019 11:19 am 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 8130
Location: Seattle
Maybe, are you driving /RST high?


Top
 Profile  
 
 Post subject: Re: Switching ROM banks
PostPosted: Mon Feb 11, 2019 3:01 pm 
Offline

Joined: Mon Feb 04, 2019 8:47 am
Posts: 8
Nope, the same code is being run against both cartridges so my thought was that there is something to do with the different MBCs or maybe that the Game Boy color sent some different signals than the original Game Boy.


Top
 Profile  
 
 Post subject: Re: Switching ROM banks
PostPosted: Mon Feb 11, 2019 3:05 pm 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 8130
Location: Seattle
That's what I meant. I don't know the pinouts for the MBC1 and other parts, maybe the MBC3 doesn't connect to /RST and maybe the MBC5 does, so that's why I asked if you're driving /RST.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 21 posts ]  Go to page Previous  1, 2

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