Strange Frankestein Hardware - Turn SMS into a computer

Paladin (933)

14-11-2008, 20:07

Folks,

I was philosophic thinking about modern hardware pieces for MSX, specially video cards. At the hypothetical thought I was imagining a Voodoo 3 based card for MSX!
Then it occurred me the obvious: My maximum pleasure would be to play quake on my TR? Praying for more FPS? I can do that on my modern PC which is inches away from my MSX! Same for mp3 play.
But how to re-create the old times feeling? My strange idea is:

Why not creating a cartridge for Sega Master System with:
* IDE-CF Interface
* PS/2 Connector
* 4MB Ram
* SMS Bios (can be based on C-BIOS)
* SMS-Basic, hack of MSX1 Basic using new SMS Mode 4 functions, adapting the sound functions to the different chip and creating functions to memory paging
* SMS-DOS, based on the CP/M Dos or even MSX-DOS, supporting the IDE-CF

And finally but not last important: ExecSMS.COM! That would allow the new computer to be launched with an extremely large games database...
With little effort, most msx1 software could also be ported to it, and basic programs would run automatically!!

*PS* I'm not crazy!

By Sd-Snatcher

Hero (582)

15-11-2008, 12:40

And then symbos for SMS-nator.

By muffie

Paladin (933)

24-11-2008, 13:57

That's a good idea... You guys must admit it!
A brand new computer from the past!

By mohai

Paladin (1007)

24-11-2008, 18:28

Nice!

SMS and MSX are quite similar...
Did you think about it could be easier to connect SMS VDP to MSX? Remember that MSXs do have keyboard, IDE, more RAM... imaging a SMSX or something....

By muffie

Paladin (933)

24-11-2008, 19:13

I do imagine that quite often.
In theory, just replacing the VDP of a MSX1 with the SMS one would still make the machine capable of running anything made for MSX1...

By Jipe

Paragon (1614)

24-11-2008, 19:29

have you the pin out of SMS VDP ?

By sinus

Expert (85)

24-11-2008, 20:39

In theory, just replacing the VDP of a MSX1 with the SMS one would still make the machine capable of running anything made for MSX1...

Would it? I thought it was just derived from it but still quite far away.
That'd be good news!

By mohai

Paladin (1007)

25-11-2008, 12:35

SMS VDP is nothing but a "evolution" from the original 9918 with an extra bitmap mode. It also has the legacy modes (some say it lacks from text 0), so backwards compatibility is true.
An advantage is that SMS joined sound chip, VDP and some other functions in a single chip.

Here is the pinout. SMS Schemes should be somewhere in the net, but you can also try

www.getlofi.com/?p=125
www.getlofi.com/uploaded_images/M3vdp-739225.png
www2.odn.ne.jp/%7Ehaf09260/Mark3/EnrM3.htm

1 CD0 64 /INT
2 CD1 63 CA7*
3 CD2 62 CA6*
4 CD3 61 CA0*
5 CD4 60 /IORQ
6 CD5 59 /WR
7 CD6 58 /RD
8 CD7 57 PAL/NTSC (SWITCH)
9 GND 56 AD15
10 AUDIO (OUT) 55 AD14
11 VCC 54 AD13
12 T0 (NC?) 53 AD12
13 T1 (NC?) 52 AD11
14 /KBSEL 51 AD10
15 /RAM CS 50 AD9
16 /EXM1 49 AD8
17 /EXM2 48 AD7
18 CA14 47 AD6
19 CA15 46 AD5
20 /MREQ (IN) 45 AD4
21 /NMI OUT 44 AD3
22 /NMI IN 43 AD2
23 /RESET 42 AD1
24 /BFP 41 AD0

25 /PCP 40 VCC
26 R (OUT) 39 /CE
27 G (OUT) 38 /OE
28 B (OUT) 37 /WE1 (OUT) chip ram1
29 /CSYNC (OUT) 36 /WE0 (OUT) chip ram0
30 XTAL1 35 /N-L (NC?)
31 XTAL2 34 CPUCLK (OUT)
32 GND 33 Y1

By muffie

Paladin (933)

21-01-2009, 18:36

Mohai: So, with little modification on the pins it should be possible to just replace the 9918 with the SMS vdp? BIOS should be changed in order to boot in screen 1 (because it lacks mode 0)???

By mohai

Paladin (1007)

30-01-2009, 13:18

Theoretically, it could be possible with SOME modification. Notice that memory addressing by the SMS chip is quite different than the original 9918. SMS chip addresses two 8 bit chips together.
I think it culd be posible to add it together with the VRAM.

By iamweasel2

Paladin (713)

30-01-2009, 15:15

Since its backward compatibility is not 100% and other technical problems, wouldn't be easier to just make a cartridge with the SMS vdp? Since new software (like ExecSMS) will need to be made anyway, I believe there's no problem searching for the SMS vdp in a different port instead of the original one...