Super Magic Drive research thread

Ask anything your want about Megadrive/Genesis programming.

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tcdev
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SMD BIOS running under an emulator

Post by tcdev » Tue Apr 12, 2011 4:30 pm

That's interesting news indeed! I was thinking of porting Space Invaders to the SMD, using the VDP for the graphics, but wasn't sure if there was an emulator that could readily execute the SMD BIOS code...

Another possibility I thought of was porting the MSX version of Lode Runner, which uses a similar VDP, but would need at least 32KB of code space...

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Post by Koji » Wed Apr 13, 2011 12:46 am

Hi!..
I just recently became the proud owner of a SMD that I found in the wild. I must confess that I don't really know much about this device other than the basics.
While doing some research I found this great thread, with awesome info and the amazing work done by you guys.

I have a question though.. My SMD is supposedly a 16M unit, it has the same exact board as shown here:

http://www.videogameobsession.com/video ... ier-04.jpg

The battery leaked doing some damage to the board and I removed it. Unfortunately, I don't have the FDD for further testing but Genesis carts play fine when accessing the main menu..

Now, when I first boot the SMD with no cartridge, I get greeted by a green screen. My question is, shouldn't the menu display RAM "16M" rather than the RAM "8M" ?... :?:



...
Last edited by Koji on Sun May 08, 2011 2:54 am, edited 3 times in total.

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Post by LocalH » Wed Apr 13, 2011 1:32 am

"MAGIC DRIVER V-1"? It'd probably be cool to dump that BIOS using Charles' smdutil.

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Post by KanedaFr » Wed Apr 13, 2011 7:44 am

Hi,
give us a pic of the RAM board and we'll be able to tell you if you have a 8M or a problem with a track on your board preventing access to the upper 8M...
you could also use tcdev's DRAM board schematic for reference
perhaps yours is different (like mine) but the connector pinout is the same

and I second LocalH : we don't know what the v1 driver is yet!
share it and I'll comment it like the others one....and see if there is a bug in memory handling, for ex ;)

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Post by Koji » Wed Apr 13, 2011 2:45 pm

I'm just assuming its a 16M unit because there was a huge "16M" sticker on the bottom, but I would like to confirm it...

Also, I'd definitely love to share it, but I guess I can't for now since I don't even have a parallel port cable neither a floppy drive :( ....
Last edited by Koji on Sun May 08, 2011 2:55 am, edited 1 time in total.

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KanedaFr
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Post by KanedaFr » Wed Apr 13, 2011 3:07 pm

so bad :(

the pic isn't hd enougth, what is written on the 4 same IC in the ram board ?


also, other people here will confirm, but I think you should put something on the bios rom : it could be corrupted if the window see too much the sun or other strong lights...

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Post by Koji » Wed Apr 13, 2011 3:30 pm

Sorry about the pic. Those IC's are KM44C1000's (4bit D Rams each) :? .

I covered the window just in case.
Last edited by Koji on Wed Apr 13, 2011 3:46 pm, edited 3 times in total.

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Post by KanedaFr » Wed Apr 13, 2011 3:37 pm

http://www.chipdocs.com/datasheets/data ... C1000.html

so 4 chip of 1Mx4bits so 16Mbits ;)
Try to remove and clean the ram board connector...mainly pin 10 & 12 since, from tcdev schem, it's the UpperRAM select pins
else, welcome in the wonderful world of to-fix SMD ;)

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Post by Koji » Wed Apr 13, 2011 3:48 pm

Hmmm. I'll try cleaning it a little more.

Another quick question. Why is that menu showing "CARD 2M" when there isn't any cartridge in the slot?.

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Post by KanedaFr » Wed Apr 13, 2011 5:50 pm

wow! I did understand that!
I think you have a short somewhere.... or a bugged bios ;)

what happen if you plug a cart?

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Post by Koji » Wed Apr 13, 2011 6:07 pm

KanedaFr wrote: what happen if you plug a cart?
The "CARD" number changes acording to the cartridge size (2M/4M/8M). And I'm able to play the game just fine if "RUN IC CARD" is selected.

Larger games such as Sreet Fighter II change the number to "CARD 8" for example.

Is Super Street Fighter II "the new challengers" compatible with these SMD units at all?. I ask because all I get is a red screen whe trying to play it through this SMD

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Post by Stef » Wed Apr 13, 2011 6:21 pm

Koji wrote:
KanedaFr wrote: what happen if you plug a cart?
The "CARD" number changes acording to the cartridge size (2M/4M/8M). And I'm able to play the game just fine if "RUN IC CARD" is selected.

Larger games such as Sreet Fighter II change the number to "CARD 8" for example.

Is Super Street Fighter II "the new challengers" compatible with these SMD units at all?. I ask because all I get is a red screen whe trying to play it through this SMD
So you have your answer ;) A red screen means a checksum error which is typical when bank switch doesn't work...

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Post by Koji » Wed Apr 13, 2011 6:26 pm

Stef wrote:
So you have your answer ;) A red screen means a checksum error which is typical when bank switch doesn't work...
So, are you saying the Bios is at fault?.. It only happens with that game only though.

Thanks!

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Post by Stef » Wed Apr 13, 2011 6:28 pm

It's normal as this game is the only one to use Bank Switch feature (size > 32 MB). I think it's more hardware related than software.

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Post by KanedaFr » Mon Apr 18, 2011 10:03 am

Can someone explain the need to use a relay in the external FDD drive ?

Image
source: http://www.tototek.com/phpBB2/viewtopic.php?p=14110

mine is a blue Takamisawa(Fujistu) RY5W-K 5V RELAY DPDT 1A

I don't understand why it's not a pure 7805... why the need for a relay ?

ps: FFE sucks at soldering ! they soldered the 7805 like dummies!

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