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Hello everyone, I am new to the forum (I have been a visitor for a long time), but now that I have won my master system from a friend (MS3 compact), I will be able to use the forum as a registered user.
I'm trying to make my first cartridge with flash memory, but I had some doubts, after many attempts, because so far only got black screen.

I'm trying to make a cartridge with no memory mapping (I believe only 32k worked), for that I used the shinobi cartridge (single chip 32 pins) and my memory W29EE011-15.

I have studied the following materials:
http://little-scale.blogspot.com.br/2008/06/how-to-make-32kb-sega-master-system.... (the chip has fewer pins and the board is different from mine)

http://www.smspower.org/Development/SMSReader-32KCartridge
(seems to have more than I need, because for the time I do not need to save with battery ... also works with SRAM, and I intend to work with flash / eprom)

I also looked at this: http://www.smspower.org/forums/14087-MakingAMasterSystemFlashEEPROMCartridge

I looked at the work of Mike G.

I looked at some other works as well: http://dreamjam.co.uk/emuviews/smsflash.php

The doubts that still persist:
Game I tested: ted boy
Do I need to use swap byte as in megadrive?
Are these roms good (emuparadise / romhustler / coolrom etc) or do they contain checksum errors etc?
Could someone give me a good rom address for testing?

As far as I could tell, the maskrom of my MPR-14326 cartridge (compared to the cartridge connector pins) seems to have fewer addresses than my FLASH W29EE011-15 ... (seems to have the A16 left) what to do with these addresses left in my flash? I land them? I turn on 5V?

And the pins WE OE CE (I land on 5V?)

I'm using a willem recorder to record the flash.

Sorry for the bad links, because I get an error message because I am a new user and can not post links. (How many posts do I need to be able to post links?)

Thank you all for your help.

I activated your links, we have to be brutal to avoid spam.

No byte swapping is necessary. Occasionally you may find some headers or footers which need to be removed, you may use SMS Checker to validate and fix but mostly there are very few bad dumps around.

Every usable ROM will have "TMR SEGA" at 0x7ff0, if you want to validate.

You should be able to get that working without too much trouble.

I suggest soldering a 32 pin IC socket to your board to make things a little easier. Bend pins 1, 2, 3, 31 and 32 of the socket out the side so you can solder wires onto them. Pin 4 of your socket should then go into the same place as pin 2 of the original mask rom. The socket should fit straight in.

Most of the pins are already correct now, its just the extra ones that we bent over on the socket that we need to take care of. A15 (Pin 3) and A16 (Pin 2) both need to be tied to ground. I would connect /WE (Pin 31) to +5v and you'll need to connect VDD (Pin 32) to +5v too. From there it should be good to go.

You shouldn't need to byte swap either.

Thank you so much guys.
I will try to do in the next few days, and post here the result.

I want to thank you guys, the game worked (I tested it with teddyboy 32kb)

The pins at the end looked like this.
Pin 1 (I left disconnected - in the datasheet it said that it had no function, so I do not know if it made a difference, but I left it disconnected anyway)

Pin 2 and pin 3 (A16 / A15 - floating - grounded)

Pin 31 (WE Connected to + 5v)

========
Although it worked, I did not understand some things:

I was plugging the A15 pin of the flash memory into the A15 pin of the SLOT ... should not it have worked?

The OE pin of the flash memory Originally stayed connected where would the A15 pin (in SLOT) this pin should not be in the ground?

Wasup said: "Pin 4 of your socket should then go into the same place as the pin 2 of the original mask rom" I did not understand this part properly, because the pin 2 of the maskrom seems not to be connected. (but worked without this connection)

I heard that for cartridges without the memory mapping chip I could only use 32kb games ... But the rom of the shinobi net (original of my test card) is bigger than that ... this information on the 32kb is true ? how can shinobi work without the memory mapping chip?

Part of my mistakes were to use a rom hack (Geraldinho-BR) I verified through the MAXIM programs that the checksum was wrong, but I did not find the option to correct the error. In this case only by manually correcting?

For this memory mapping chip is there a commercial version? or just withdrawing from donor cartridges?

Thank you all for the great help.

There aren't any homebrew mapper chips available, although some have been designed for CPLDs.

A15 and A16 are for accessing memory past 32KB. The slot signals tell you when the CPU is accessing higher than that but it's not expecting the cartridge to respond.

Hacks often don't have a valid checksum, but we avoid patching them as it causes ROM collection proliferation.

As Maxim said, A15 and A16 are used for accessing ROM space above 32KB. You could connect A15 on your flash rom to A15 on the cart pcb and it will still work, how ever A16 would still need to be grounded.

The OE pin is used to enable the data coming out of the ROM. Its an active low signal, meaning the data gets output when its connected to ground. Its connected to A15 on the cart pcb so that data is output to the CPU only when its accessing 0KB to 32KB.

You can actually have a game thats up to 48KB without needing a mapper. Some games have external mappers, other games had them built inside the mask ROM. Your Shinobi ROM will have the mapper built inside it.

Thank you so much guys. I really enjoyed the tips. I understand perfectly.

Author	Message
clopes Joined: 19 Feb 2018 Posts: 8 Location: Brazil	Changing MASKROM/Flash? Posted: Sat Feb 24, 2018 10:41 pm
clopes Joined: 19 Feb 2018 Posts: 8 Location: Brazil	Hello everyone, I am new to the forum (I have been a visitor for a long time), but now that I have won my master system from a friend (MS3 compact), I will be able to use the forum as a registered user. I'm trying to make my first cartridge with flash memory, but I had some doubts, after many attempts, because so far only got black screen. I'm trying to make a cartridge with no memory mapping (I believe only 32k worked), for that I used the shinobi cartridge (single chip 32 pins) and my memory W29EE011-15. I have studied the following materials: http://little-scale.blogspot.com.br/2008/06/how-to-make-32kb-sega-master-system.... (the chip has fewer pins and the board is different from mine) http://www.smspower.org/Development/SMSReader-32KCartridge (seems to have more than I need, because for the time I do not need to save with battery ... also works with SRAM, and I intend to work with flash / eprom) I also looked at this: http://www.smspower.org/forums/14087-MakingAMasterSystemFlashEEPROMCartridge I looked at the work of Mike G. I looked at some other works as well: http://dreamjam.co.uk/emuviews/smsflash.php The doubts that still persist: Game I tested: ted boy Do I need to use swap byte as in megadrive? Are these roms good (emuparadise / romhustler / coolrom etc) or do they contain checksum errors etc? Could someone give me a good rom address for testing? As far as I could tell, the maskrom of my MPR-14326 cartridge (compared to the cartridge connector pins) seems to have fewer addresses than my FLASH W29EE011-15 ... (seems to have the A16 left) what to do with these addresses left in my flash? I land them? I turn on 5V? And the pins WE OE CE (I land on 5V?) I'm using a willem recorder to record the flash. Sorry for the bad links, because I get an error message because I am a new user and can not post links. (How many posts do I need to be able to post links?) Thank you all for your help.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14744 Location: London	Posted: Sun Feb 25, 2018 6:46 am
	I activated your links, we have to be brutal to avoid spam. No byte swapping is necessary. Occasionally you may find some headers or footers which need to be removed, you may use SMS Checker to validate and fix but mostly there are very few bad dumps around. Every usable ROM will have "TMR SEGA" at 0x7ff0, if you want to validate.

wasup Joined: 05 Nov 2014 Posts: 435 Location: Auckland - NZ	Posted: Sun Feb 25, 2018 8:21 am
	You should be able to get that working without too much trouble. I suggest soldering a 32 pin IC socket to your board to make things a little easier. Bend pins 1, 2, 3, 31 and 32 of the socket out the side so you can solder wires onto them. Pin 4 of your socket should then go into the same place as pin 2 of the original mask rom. The socket should fit straight in. Most of the pins are already correct now, its just the extra ones that we bent over on the socket that we need to take care of. A15 (Pin 3) and A16 (Pin 2) both need to be tied to ground. I would connect /WE (Pin 31) to +5v and you'll need to connect VDD (Pin 32) to +5v too. From there it should be good to go. You shouldn't need to byte swap either.

clopes Joined: 19 Feb 2018 Posts: 8 Location: Brazil	Posted: Sun Feb 25, 2018 7:14 pm
clopes Joined: 19 Feb 2018 Posts: 8 Location: Brazil	Thank you so much guys. I will try to do in the next few days, and post here the result.

clopes Joined: 19 Feb 2018 Posts: 8 Location: Brazil	Posted: Wed Feb 28, 2018 7:07 am
clopes Joined: 19 Feb 2018 Posts: 8 Location: Brazil	I want to thank you guys, the game worked (I tested it with teddyboy 32kb) The pins at the end looked like this. Pin 1 (I left disconnected - in the datasheet it said that it had no function, so I do not know if it made a difference, but I left it disconnected anyway) Pin 2 and pin 3 (A16 / A15 - floating - grounded) Pin 31 (WE Connected to + 5v) ======== Although it worked, I did not understand some things: I was plugging the A15 pin of the flash memory into the A15 pin of the SLOT ... should not it have worked? The OE pin of the flash memory Originally stayed connected where would the A15 pin (in SLOT) this pin should not be in the ground? Wasup said: "Pin 4 of your socket should then go into the same place as the pin 2 of the original mask rom" I did not understand this part properly, because the pin 2 of the maskrom seems not to be connected. (but worked without this connection) I heard that for cartridges without the memory mapping chip I could only use 32kb games ... But the rom of the shinobi net (original of my test card) is bigger than that ... this information on the 32kb is true ? how can shinobi work without the memory mapping chip? Part of my mistakes were to use a rom hack (Geraldinho-BR) I verified through the MAXIM programs that the checksum was wrong, but I did not find the option to correct the error. In this case only by manually correcting? For this memory mapping chip is there a commercial version? or just withdrawing from donor cartridges? Thank you all for the great help.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14744 Location: London	Posted: Wed Feb 28, 2018 7:30 am
	There aren't any homebrew mapper chips available, although some have been designed for CPLDs. A15 and A16 are for accessing memory past 32KB. The slot signals tell you when the CPU is accessing higher than that but it's not expecting the cartridge to respond. Hacks often don't have a valid checksum, but we avoid patching them as it causes ROM collection proliferation.

wasup Joined: 05 Nov 2014 Posts: 435 Location: Auckland - NZ	Posted: Wed Feb 28, 2018 9:39 am
	As Maxim said, A15 and A16 are used for accessing ROM space above 32KB. You could connect A15 on your flash rom to A15 on the cart pcb and it will still work, how ever A16 would still need to be grounded. The OE pin is used to enable the data coming out of the ROM. Its an active low signal, meaning the data gets output when its connected to ground. Its connected to A15 on the cart pcb so that data is output to the CPU only when its accessing 0KB to 32KB. You can actually have a game thats up to 48KB without needing a mapper. Some games have external mappers, other games had them built inside the mask ROM. Your Shinobi ROM will have the mapper built inside it.

clopes Joined: 19 Feb 2018 Posts: 8 Location: Brazil	Posted: Wed Feb 28, 2018 10:00 am
clopes Joined: 19 Feb 2018 Posts: 8 Location: Brazil	Thank you so much guys. I really enjoyed the tips. I understand perfectly.

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