Super Magic Drive research thread
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I know it's a bit off topic, but if I had been making the SEGA CD, it would look just like the SMD. Look at an image of a SMD and tell me you don't think "CD" right off the bat. Have it flip open right in the middle with the circuit board above the CD with the cart slot attached so it's right where the cart slot in the SMD is. Plugging in the cart slot would have made the CD more flexible and given the chance to put a simple 256 color framebuffer in it for improved graphics.
Yes, my immediate thought looking at the SMD is Jaguar CD. Is that it?
I don't care to be the one to second-guess the Sega CD. But with a framebuffer and improved color depth, it would have been quite intriguing -- a whole different ballgame, even. It's a nice fantasy. That said, I kinda enjoy the system for what it is.
I don't care to be the one to second-guess the Sega CD. But with a framebuffer and improved color depth, it would have been quite intriguing -- a whole different ballgame, even. It's a nice fantasy. That said, I kinda enjoy the system for what it is.
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Exactly. You can't look at the SMD and not think it... well, in my opinion, at least. I think it looks cooler than either the model 1 or 2 CD as well.TascoDLX wrote:Yes, my immediate thought looking at the SMD is Jaguar CD. Is that it?
I don't think the extra 68000 was really needed - just ram for the MD CPU to use for programs/data loaded from CD, and the ASIC/framebuffer. Kinda on the fence about the PCM chip. They could have left it out if they wished to keep the price down. I think SEGA only added it because the PCE CD had an ADPCM chip in it.I don't care to be the one to second-guess the Sega CD. But with a framebuffer and improved color depth, it would have been quite intriguing -- a whole different ballgame, even. It's a nice fantasy. That said, I kinda enjoy the system for what it is.
I stopped fighting with LPT port on windows , I use a linux just for this.
Else, look at ucon64 page, there is a LPT driver for windows which I remember I used before
(http://ucon64.sourceforge.net/) and I think you should be able to get info from their faq
If you succeed, don't forget to send it to me so I can disassemble it
Else, look at ucon64 page, there is a LPT driver for windows which I remember I used before
(http://ucon64.sourceforge.net/) and I think you should be able to get info from their faq
If you succeed, don't forget to send it to me so I can disassemble it
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Hi all !
I realized today that i have a smd with an undumped/unknown bios 3.3C .
So i have dumped it with my double pro fighter .
the difference between 3.3 & 3.3c : in the menu "load file , save file " is back again like in 3.1g version !
https://rapidshare.com/files/458231229/bios3.3c.rar
I realized today that i have a smd with an undumped/unknown bios 3.3C .
So i have dumped it with my double pro fighter .
the difference between 3.3 & 3.3c : in the menu "load file , save file " is back again like in 3.1g version !
https://rapidshare.com/files/458231229/bios3.3c.rar
I'm back to the office so I was able to take some times for this
http://gendev.spritesmind.net/files/bsy ... alysis.zip
Not a lot of new stuff :
- (re)add the way to load/dump in/from DRAM (like greatfunky already said)
- removed some unused code (some more still here)
It's cleary the best of the bios with 16k page
I also started to port the 3.3c bios to WLA DX so it will be a open source bios 'soon'
http://gendev.spritesmind.net/files/bsy ... alysis.zip
Not a lot of new stuff :
- (re)add the way to load/dump in/from DRAM (like greatfunky already said)
- removed some unused code (some more still here)
It's cleary the best of the bios with 16k page
I also started to port the 3.3c bios to WLA DX so it will be a open source bios 'soon'
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There is something I don't understand....
On every bios, there is a vector table
How these interrup handler are called ?
RESET is called at startup, ok...but what about the others ?
I didn't find any rst XX on disassemby so I assume it's an hw interrupt call (strage for a "print_msg_at_HL"!)
from Charles's SMS tech doc,
Note all but RESET are in fact called from anywhere on the code and use a basic "ret" not "retn" so I suspect the vector table is invalid.
What do you think ?
On every bios, there is a vector table
Code: Select all
.org $0000
jp RESET
jp print_hexascii_byte
jp print_msg_at_HL
jp VDP_cls
jp init_VDP_and_character_set
jp loadCartInDRAM
jp handle_pc_command
RESET is called at startup, ok...but what about the others ?
I didn't find any rst XX on disassemby so I assume it's an hw interrupt call (strage for a "print_msg_at_HL"!)
from Charles's SMS tech doc,
but, unless I missed something, the INT isn't connected on Genny so this can't happen...The interrupting device can place a single or multi-byte opcode on the
data bus for the Z80 to fetch and execute when an interrupt occurs.
Note all but RESET are in fact called from anywhere on the code and use a basic "ret" not "retn" so I suspect the vector table is invalid.
What do you think ?
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Re: Super Magic Drive research thread
This is normal practice. This table can be used by downloadable software. And these vectors will always be true, even if the system software is updated.