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Yo Eric, Charles, Omar, PrOfUnD, Ricardo, ATani, and everybody else. Howya doin'? :)

Eric has contacted me a couple of days ago asking if I wanted to share SMS devcart info. I then concluded that it would be more efficient to post data on S8 than to exchange mail privately. (Besides, my mail server s***s donkey d**k.)
So here it is. It's by no means complete, but it should hopefully come in handy as a hitchhiker's guide to Devcartland. :)

FLAVIO'S HOMEMADE DEVCARTS, CHAPTER ONE: THE SMS
------------------------------------------------

(License notice: All schematics and the doc itself are freely distributable.
If you want to make them available for download on your site, go ahead, you
have my blessing.)

THE QUICK AND THE DIRTY: EPROM CARTS
------------------------------------

Those are undoubtedly the easiest to build, as long as the user already
owns an EPROM programmer and eraser. 27256's don't have any commercial
value anymore, and can be obtained in large amounts for next to nothing.
I very often forget a bunch of them lying on the ground, and then step
on them bare-footedly, with rather painful results. :o)
Just like with every minimal design, actual usage of those devices isn't
optimal at all, i. e. constantly erasing and programming an EPROM are
time-consuming tasks, and will slow down your research. (Although I've
been told that's how Ocean, the British software house, made their NES
games. NES and EPROM programming. Gross. Poor kids.)
Anyway, it may be a good start for rookie hardware h4X0rZ. I've uploaded
the schematic for one of those thingies to
my
Geocities account. It's "sort-of-GNU" hardware, so if you ever derive
any work from it, you're demanded to distribute the "source".
We already have enough undisclosed proprietary hardware, thankyouverymuch. :/
The editor/viewer for those PCB files is also

there. (This ain't a site plug 'cuz I don't even mantain a site, mind you.)
Oh yeah, sell any of those things for profit and I'll rip your nads off
with a rusty monkey wrench.
On the other hand, if you can build and deliver these things to emu authors
and console programmers for prices below USD30 (no profit... see above),
please do ASAP. I'm afraid I won't be able to fulfill the demand.
Besides, it ain't easy (or cheap) to get things built and shipped abroad,
in Brazil. ~:(

Beware of local regulations: The SMS may be classified as "military
supercomputer" on some countries. Yes, this is meant to be offensive. >:)

A BIT LESS LAME: 28F010 FLASH ROMS
----------------------------------

Flash ROMs slightly reduce the pain on one's rear end by not requiring
twenty interminable minutes under ultraviolet light. It still needs
the ever-so-popular EPROM programmer though.

This schematic can be used both with 27010/27C010 EPROMs and 28F010
Flash ROMs.

SILICON AMNESIA: 62256 SRAMS
----------------------------

Very nice in theory, SRAMs have one shortcoming: An otherwise undetectable
bus glitch happens and presto, your program is history. There are two
ways to work around this limitation:

1) Battery-backup control ICs

There is a number of "please don't let the SRAM kill my data" integrated
circuits. I've fiddled with a bunch of Dallas components, but none of them
managed to defend the cart against more intense glitches without human
interaction (i. e. a switch on the cart.)
This model requires an SMS dumper (otherwise, how would you write anything
to it?)
Schematics haven't reached a final form yet. (In other words, the carts
still suck.) I'll publish them as soon as they're ready for public
consumption.

2) Devcart managed by console itself.

This is the concept behind some of the truckload of different Genesis
devcarts I've designed. Unfortunately, it would take lots of components
to do this on an SMS. Pity... It's real simple on Gennies. :(

I'M SURE DRAMS WILL DO... OR WILL THEY?
---------------------------------------

DRAMs are tools of Satan. Smash them to tiny bits with a lump hammer.
Then set the debris afire. Then pee on the ashes. You guessed right, I
hate them.

BUT I WANT TO USE IT ON THE GAME GEAR!
--------------------------------------

No problemo, modify a Master Gear adapter so it grounds /GG (pin 42.)
(That's what I've done, and it works fine. All I need now is to purchase
a GG, but that's way off topic.)

'ERE, GUV'NOR, 32KB STINK, 'OW 'BOUT DA BLOODY BANKIN', EH?
-----------------------------------------------------------

Indeed, 32KB are as wide and agreeable as a public restroom. But I'll
tell you the truth: Unless you employ some sort of programmable device
like a FPGA, a homemade SMS devcart with built-in banker will wind up being
two feet tall. Conversely, most FPGAs will bleed your batteries dry, if you
use the cart on a GG.
I'm attempting to minimize its size as we speak. I believe an EPROM (being
used as programmable gate array), along with a 74138, a couple of
74374's, and a 29F040 will do. Then again, maybe not. :/

And that's all for now, folks.
... I wonder if leaving the 0-16KB range unpageable would actually break game
compatibility? Oh well. I'll let you know as soon as I get anything working.

Cheers,
F.

Nice document.
I was working on a hack recently which did consist in uploading my code to the SRAM of a game (Golden Axe Warrior) in my case, and h4x0r the game with an Action Replay (which modify RAM directory and not ROM accesses) to make it jump to the specified location.
Problem is that I don't know when the PAR is nice enough to modify the RAM location I choosen. Having to modify a location that is used to store a PC before a function RETurn, it's quite a pain to find a place for this that be can done inside of the game without screwing the rest.

All your files points to 404 errors, by the way :P

Quote

> Nice document.

Not really... It still leaves an awful lot uncovered.

Quote

> I was working on a hack recently which did consist in uploading my code to the SRAM of a game (Golden Axe Warrior) in my case, and h4x0r the game with an Action Replay (which modify RAM directory and not ROM accesses) to make it jump to the specified location.
> Problem is that I don't know when the PAR is nice enough to modify the RAM location I choosen. Having to modify a location that is used to store a PC before a function RETurn, it's quite a pain to find a place for this that be can done inside of the game without screwing the rest.

Blimey. That was definitely creative. But I'm tired of seeing people having to resort to strange hardware kludges in order to run code on consoles. Let's get those damn devcarts built and kiss that stupid limitation goodbye. :)

Quote

> All your files points to 404 errors, by the way :P

I've tested them, one by one, a few minutes after posting the doc. Geocities has gone whacko. Try saving the files to disc or changing filenames to all caps. Damned be Geocities. ~:(
Let's see... Check it out, they do work if you paste them on the URL window. Go figure. O_O

Cheers,
F.

Author	Message
Flavio Guest	SMS/GG devcarts, tome one. Posted: Fri Apr 21, 2000 5:57 am
Flavio Guest	Yo Eric, Charles, Omar, PrOfUnD, Ricardo, ATani, and everybody else. Howya doin'? :) Eric has contacted me a couple of days ago asking if I wanted to share SMS devcart info. I then concluded that it would be more efficient to post data on S8 than to exchange mail privately. (Besides, my mail server s*s donkey dk.) So here it is. It's by no means complete, but it should hopefully come in handy as a hitchhiker's guide to Devcartland. :) FLAVIO'S HOMEMADE DEVCARTS, CHAPTER ONE: THE SMS ------------------------------------------------ (License notice: All schematics and the doc itself are freely distributable. If you want to make them available for download on your site, go ahead, you have my blessing.) THE QUICK AND THE DIRTY: EPROM CARTS ------------------------------------ Those are undoubtedly the easiest to build, as long as the user already owns an EPROM programmer and eraser. 27256's don't have any commercial value anymore, and can be obtained in large amounts for next to nothing. I very often forget a bunch of them lying on the ground, and then step on them bare-footedly, with rather painful results. :o) Just like with every minimal design, actual usage of those devices isn't optimal at all, i. e. constantly erasing and programming an EPROM are time-consuming tasks, and will slow down your research. (Although I've been told that's how Ocean, the British software house, made their NES games. NES and EPROM programming. Gross. Poor kids.) Anyway, it may be a good start for rookie hardware h4X0rZ. I've uploaded the schematic for one of those thingies to my Geocities account. It's "sort-of-GNU" hardware, so if you ever derive any work from it, you're demanded to distribute the "source". We already have enough undisclosed proprietary hardware, thankyouverymuch. :/ The editor/viewer for those PCB files is also there. (This ain't a site plug 'cuz I don't even mantain a site, mind you.) Oh yeah, sell any of those things for profit and I'll rip your nads off with a rusty monkey wrench. On the other hand, if you can build and deliver these things to emu authors and console programmers for prices below USD30 (no profit... see above), please do ASAP. I'm afraid I won't be able to fulfill the demand. Besides, it ain't easy (or cheap) to get things built and shipped abroad, in Brazil. ~:( Beware of local regulations: The SMS may be classified as "military supercomputer" on some countries. Yes, this is meant to be offensive. >:) A BIT LESS LAME: 28F010 FLASH ROMS ---------------------------------- Flash ROMs slightly reduce the pain on one's rear end by not requiring twenty interminable minutes under ultraviolet light. It still needs the ever-so-popular EPROM programmer though. This schematic can be used both with 27010/27C010 EPROMs and 28F010 Flash ROMs. SILICON AMNESIA: 62256 SRAMS ---------------------------- Very nice in theory, SRAMs have one shortcoming: An otherwise undetectable bus glitch happens and presto, your program is history. There are two ways to work around this limitation: 1) Battery-backup control ICs There is a number of "please don't let the SRAM kill my data" integrated circuits. I've fiddled with a bunch of Dallas components, but none of them managed to defend the cart against more intense glitches without human interaction (i. e. a switch on the cart.) This model requires an SMS dumper (otherwise, how would you write anything to it?) Schematics haven't reached a final form yet. (In other words, the carts still suck.) I'll publish them as soon as they're ready for public consumption. 2) Devcart managed by console itself. This is the concept behind some of the truckload of different Genesis devcarts I've designed. Unfortunately, it would take lots of components to do this on an SMS. Pity... It's real simple on Gennies. :( I'M SURE DRAMS WILL DO... OR WILL THEY? --------------------------------------- DRAMs are tools of Satan. Smash them to tiny bits with a lump hammer. Then set the debris afire. Then pee on the ashes. You guessed right, I hate them. BUT I WANT TO USE IT ON THE GAME GEAR! -------------------------------------- No problemo, modify a Master Gear adapter so it grounds /GG (pin 42.) (That's what I've done, and it works fine. All I need now is to purchase a GG, but that's way off topic.) 'ERE, GUV'NOR, 32KB STINK, 'OW 'BOUT DA BLOODY BANKIN', EH? ----------------------------------------------------------- Indeed, 32KB are as wide and agreeable as a public restroom. But I'll tell you the truth: Unless you employ some sort of programmable device like a FPGA, a homemade SMS devcart with built-in banker will wind up being two feet tall. Conversely, most FPGAs will bleed your batteries dry, if you use the cart on a GG. I'm attempting to minimize its size as we speak. I believe an EPROM (being used as programmable gate array), along with a 74138, a couple of 74374's, and a 29F040 will do. Then again, maybe not. :/ And that's all for now, folks. ... I wonder if leaving the 0-16KB range unpageable would actually break game compatibility? Oh well. I'll let you know as soon as I get anything working. Cheers, F.

Zoop Joined: 24 Jun 1999 Posts: 1732 Location: Paris, France	Posted: Fri Apr 21, 2000 6:58 am
	Nice document. I was working on a hack recently which did consist in uploading my code to the SRAM of a game (Golden Axe Warrior) in my case, and h4x0r the game with an Action Replay (which modify RAM directory and not ROM accesses) to make it jump to the specified location. Problem is that I don't know when the PAR is nice enough to modify the RAM location I choosen. Having to modify a location that is used to store a PC before a function RETurn, it's quite a pain to find a place for this that be can done inside of the game without screwing the rest. All your files points to 404 errors, by the way :P

Flavio Guest	Posted: Fri Apr 21, 2000 8:26 am
Flavio Guest	Quote > Nice document. Not really... It still leaves an awful lot uncovered. Quote > I was working on a hack recently which did consist in uploading my code to the SRAM of a game (Golden Axe Warrior) in my case, and h4x0r the game with an Action Replay (which modify RAM directory and not ROM accesses) to make it jump to the specified location. > Problem is that I don't know when the PAR is nice enough to modify the RAM location I choosen. Having to modify a location that is used to store a PC before a function RETurn, it's quite a pain to find a place for this that be can done inside of the game without screwing the rest. Blimey. That was definitely creative. But I'm tired of seeing people having to resort to strange hardware kludges in order to run code on consoles. Let's get those damn devcarts built and kiss that stupid limitation goodbye. :) Quote > All your files points to 404 errors, by the way :P I've tested them, one by one, a few minutes after posting the doc. Geocities has gone whacko. Try saving the files to disc or changing filenames to all caps. Damned be Geocities. ~:( Let's see... Check it out, they do work if you paste them on the URL window. Go figure. O_O Cheers, F.

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