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Does anyone have one? If so would you be willing to test something for me? Easy test, quick and no interaction required.

Is a Master EverDrive ok or do you need something custom?

Hello,

I build a 4MB card with mapper at slot 2 handling only (reg 0xFFFF). This card passed successfully testes, but game work badly/or not at all. Im interesting by all thinks that can help me figure out my problem.

So, if you want, I could test your ROM (Assuming its slot 2 switching only). But be warned that my card is not totally operational.

sverx wrote

Is a Master EverDrive ok or do you need something custom?

I was under the impression that the EverDrive only supports up to 1MB, but I might be wrong.

Thanks for the offer leviathan but it uses bank switching on 1 and 2. Unfortunately I don't know much about creating a mapper so cannot help :(

Everdrive only supports 1MB :( I appreciate Krikzz's work with his everdrives however the master system could use some improvement. Where did db go?

Kagesan wrote

sverx wrote

Is a Master EverDrive ok or do you need something custom?

I was under the impression that the EverDrive only supports up to 1MB, but I might be wrong.

No, you're right, it was me who didn't read the post well enough :|
Sorry psidum!

psidum wrote

Where did db go?

We should insist he restarts working on its SMS homebrew cart!

I didn't go anywhere - just went into full read-only mode for years!

I wrote a VHDL Sega Mapper a while ago:
https://github.com/db-electronics/SMSFlashCart/blob/master/SimpleMapper/src/SMSCart.vhd.
http://db-electronics.ca/wiki/wikis/projects/master-system-carts/

The mapping registers use 6 bits to define the :current page. This allows to map 8Mbits of ROM into the slots. I suppose if we were to extend the mapping registers to 8 bits we could in theory support ROM chips with 2 more address bits (A0 - A21, as opposed to A0 - A19).

My current CPLD (EPM3064) wouldn't support this as I am completely out of resources on it. I would need to upgrade to an EPM3128 and make a new rev of PCB to test this.

I currently lack the means to make a 4Mbyte prototype cartridge following the design of my current 512Kbyte design (SLOT1/2 mapping).

I want to make it happen through this year but can't promise it will be done nor that it will be user-friendly. Current designs and prototypes (2MByte) still require an off-cart flash programmer.

If it requires off-cart burners, then so be it. As long as the hardware exists at all in the first place! :)

Flygon wrote

If it requires off-cart burners, then so be it. As long as the hardware exists at all in the first place! :)

Mine is currently the same right now. I currently use SMT flash chips but I'm branching the PCB for a version with DIP flash. My goal would be to provide the Cart PCB with CPLD pre-installed and the end-user can install the Flash.

NeonMan wrote

I want to make it happen through this year but can't promise it will be done nor that it will be user-friendly. Current designs and prototypes (2MByte) still require an off-cart flash programmer.

Is your design open-source? Let's collaborate and not invent the wheel twice.

Cart design uses 16V8 PLDs and off-the shelf 74-series circuits. Currently designing it around a 4Mbyte ROM from previous attempt using four 512Kbyte ROM ICs. Since using an off-cart programmer is a pain, I am trying to make room for a PIC micro so I can upload ROMs via USB.

Most of the design are available at This post and this other one. I can share further details if you are interested.

Another solution is to make a Genesis cartridge PCB for an 8bit Flash ROM and to tie #M3 to ground - essentially forcing the console into SMS mode; i.e. release your SMS game in Genesis format.

You still need the mapper chip(s) though...

TmEE wrote

You still need the mapper chip(s) though...

Yes of course, but this removes the hurdle of not having any source for brand new SMS cartridge shells.

Uhm, my Everdrive plays back Phantasy Star which is 4 Megabit? @"1 Megabit limit" o_O

1MB = 1 megabyte = 8 megabit, the largest size ever used in official SMS (or GG) games.

Author	Message
psidum Joined: 01 Jan 2014 Posts: 331	Working 4MB Flash Cart? Posted: Sun Nov 27, 2016 10:14 pm
psidum Joined: 01 Jan 2014 Posts: 331	Does anyone have one? If so would you be willing to test something for me? Easy test, quick and no interaction required.

sverx Joined: 05 Sep 2013 Posts: 3805 Location: Stockholm, Sweden	Posted: Mon Nov 28, 2016 9:08 am
	Is a Master EverDrive ok or do you need something custom?

leviatan Joined: 24 Oct 2016 Posts: 26	Posted: Mon Nov 28, 2016 9:25 am
leviatan Joined: 24 Oct 2016 Posts: 26	Hello, I build a 4MB card with mapper at slot 2 handling only (reg 0xFFFF). This card passed successfully testes, but game work badly/or not at all. Im interesting by all thinks that can help me figure out my problem. So, if you want, I could test your ROM (Assuming its slot 2 switching only). But be warned that my card is not totally operational.

Kagesan Joined: 01 Feb 2014 Posts: 876	Posted: Mon Nov 28, 2016 5:00 pm
Kagesan Joined: 01 Feb 2014 Posts: 876	sverx wrote Is a Master EverDrive ok or do you need something custom? I was under the impression that the EverDrive only supports up to 1MB, but I might be wrong.

psidum Joined: 01 Jan 2014 Posts: 331	Posted: Mon Nov 28, 2016 11:36 pm
psidum Joined: 01 Jan 2014 Posts: 331	Thanks for the offer leviathan but it uses bank switching on 1 and 2. Unfortunately I don't know much about creating a mapper so cannot help :( Everdrive only supports 1MB :( I appreciate Krikzz's work with his everdrives however the master system could use some improvement. Where did db go?

sverx Joined: 05 Sep 2013 Posts: 3805 Location: Stockholm, Sweden	Posted: Tue Nov 29, 2016 9:39 am
	Kagesan wrote sverx wrote Is a Master EverDrive ok or do you need something custom? I was under the impression that the EverDrive only supports up to 1MB, but I might be wrong. No, you're right, it was me who didn't read the post well enough :\| Sorry psidum! psidum wrote Where did db go? We should insist he restarts working on its SMS homebrew cart!

db-electronics Joined: 06 Dec 2013 Posts: 335 Location: Canada	Posted: Wed Jan 11, 2017 1:13 pm
	I didn't go anywhere - just went into full read-only mode for years! I wrote a VHDL Sega Mapper a while ago: https://github.com/db-electronics/SMSFlashCart/blob/master/SimpleMapper/src/SMSCart.vhd. http://db-electronics.ca/wiki/wikis/projects/master-system-carts/ The mapping registers use 6 bits to define the :current page. This allows to map 8Mbits of ROM into the slots. I suppose if we were to extend the mapping registers to 8 bits we could in theory support ROM chips with 2 more address bits (A0 - A21, as opposed to A0 - A19). My current CPLD (EPM3064) wouldn't support this as I am completely out of resources on it. I would need to upgrade to an EPM3128 and make a new rev of PCB to test this.

NeonMan Joined: 24 Sep 2013 Posts: 141	Posted: Thu Jan 12, 2017 9:59 am
NeonMan Joined: 24 Sep 2013 Posts: 141	I currently lack the means to make a 4Mbyte prototype cartridge following the design of my current 512Kbyte design (SLOT1/2 mapping). I want to make it happen through this year but can't promise it will be done nor that it will be user-friendly. Current designs and prototypes (2MByte) still require an off-cart flash programmer.

Flygon Joined: 30 Jun 2016 Posts: 196 Location: Melbourne, Australia	Posted: Thu Jan 12, 2017 2:08 pm
	If it requires off-cart burners, then so be it. As long as the hardware exists at all in the first place! :)

db-electronics Joined: 06 Dec 2013 Posts: 335 Location: Canada	Posted: Thu Jan 12, 2017 2:55 pm
	Flygon wrote If it requires off-cart burners, then so be it. As long as the hardware exists at all in the first place! :) Mine is currently the same right now. I currently use SMT flash chips but I'm branching the PCB for a version with DIP flash. My goal would be to provide the Cart PCB with CPLD pre-installed and the end-user can install the Flash. NeonMan wrote I want to make it happen through this year but can't promise it will be done nor that it will be user-friendly. Current designs and prototypes (2MByte) still require an off-cart flash programmer. Is your design open-source? Let's collaborate and not invent the wheel twice.

NeonMan Joined: 24 Sep 2013 Posts: 141	Posted: Mon Jan 16, 2017 12:00 am
NeonMan Joined: 24 Sep 2013 Posts: 141	Cart design uses 16V8 PLDs and off-the shelf 74-series circuits. Currently designing it around a 4Mbyte ROM from previous attempt using four 512Kbyte ROM ICs. Since using an off-cart programmer is a pain, I am trying to make room for a PIC micro so I can upload ROMs via USB. Most of the design are available at This post and this other one. I can share further details if you are interested.

db-electronics Joined: 06 Dec 2013 Posts: 335 Location: Canada	Posted: Tue Jan 17, 2017 2:02 am
	Another solution is to make a Genesis cartridge PCB for an 8bit Flash ROM and to tie #M3 to ground - essentially forcing the console into SMS mode; i.e. release your SMS game in Genesis format.

TmEE Joined: 31 Oct 2007 Posts: 853 Location: Estonia, Rapla city	Posted: Tue Jan 17, 2017 5:14 pm
	You still need the mapper chip(s) though...

db-electronics Joined: 06 Dec 2013 Posts: 335 Location: Canada	Posted: Tue Jan 17, 2017 5:55 pm
	TmEE wrote You still need the mapper chip(s) though... Yes of course, but this removes the hurdle of not having any source for brand new SMS cartridge shells.

Klangfarbe Joined: 21 Oct 2010 Posts: 47 Location: Space	Posted: Mon Feb 06, 2017 1:01 am
Klangfarbe Joined: 21 Oct 2010 Posts: 47 Location: Space	Uhm, my Everdrive plays back Phantasy Star which is 4 Megabit? @"1 Megabit limit" o_O

KingMike Joined: 14 Oct 2008 Posts: 510	Posted: Mon Feb 06, 2017 2:43 am
KingMike Joined: 14 Oct 2008 Posts: 510	1MB = 1 megabyte = 8 megabit, the largest size ever used in official SMS (or GG) games.

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