pinout sega genesis cartridge slot

For hardware talk only (please avoid ROM dumper stuff)
bastien
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pinout sega genesis cartridge slot

Post by bastien » Mon Aug 09, 2010 10:13 am

hi,
i search the pinout of the cartridge slot of the sega genesis and the master system for making my own adaptator.

i have found this :

http://devster.monkeeh.com/sega/sega2sms.png

but the rewiring of the sega slot is not the same as this:

http://nintendoallstars.w.interia.pl/romlab/genconn.htm

especially for A7 pin03 ,A8 pin61 and A10, A17 pin 59

i have made this Open excel document:

http://sega4ever.power-heberg.com/tutod ... wiring.xls

TmEE co.(TM)
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Post by TmEE co.(TM) » Tue Aug 10, 2010 12:50 pm

Mida sa loed ? Nagunii aru ei saa ;)
http://www.tmeeco.eu
Files of all broken links and images of mine are found here : http://www.tmeeco.eu/FileDen

bastien
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Post by bastien » Tue Aug 10, 2010 2:52 pm

Very thanks :lol:
but i have a thing i can't understand :shock:

in a sega PCB , maskrom A18 is connected to B7 just like this picture:

Image

and in your document A18 is connected to B6 in the cartridge slot , why ?

HardWareMan
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Post by HardWareMan » Tue Aug 10, 2010 4:40 pm

bastien wrote:Very thanks :lol:
but i have a thing i can't understand :shock:

in a sega PCB , maskrom A18 is connected to B7 just like this picture:

Image

and in your document A18 is connected to B6 in the cartridge slot , why ?
Because, there are no "A0" in slot. It's 16-bit. ROM addresses numbered as "A0".."A18", and system signals used as "A1".."A19". That's confusing, when do not understanding 16bit architecture, but it's ok.

bastien
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Post by bastien » Tue Aug 10, 2010 5:02 pm

ok now i understand.
thanks all for your help

KanedaFr
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Post by KanedaFr » Tue Aug 10, 2010 8:01 pm

yep, thanks
It's an interesting document, specialy the "Description" column
about B17, does it mean that if have !cartin high, the CD could access the cart content ?
and about B31, there is nothing at $A13000-$A130FF ?!
and about ext port !ROM A21, if a cart is inserted, it gives you a direct access to the rom ?!...wait...it's an output pin...wtf...?!

HardWareMan
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Post by HardWareMan » Wed Aug 11, 2010 6:15 am

KanedaFr wrote:yep, thanks
It's an interesting document, specialy the "Description" column
about B17, does it mean that if have !cartin high, the CD could access the cart content ?
and about B31, there is nothing at $A13000-$A130FF ?!
and about ext port !ROM A21, if a cart is inserted, it gives you a direct access to the rom ?!...wait...it's an output pin...wtf...?!
Yep. !CART signal swaps !ROM and !CE0 signals. If !CART=log.1, !ROM=000000..3FFFFF and !CE0=400000..7FFFFF and vise versa when !CART=log.0, then !ROM=400000..7FFFFF and !CE0=000000..3FFFFF. So, both areas are accessable. About !TIME - it's true, $A13000-$A130FF are right area, and there is !FDC, wich on ext port and mapped to $A12000-$A120FF. But, there are not enough address lines on ext port, so you are limited by 256Kbytes (1MBytes on some MD2 models - two addresses was added VA18 and VA19).

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Post by KanedaFr » Thu Aug 12, 2010 9:08 pm

HardWareMan wrote:But, there are not enough address lines on ext port, so you are limited by 256Kbytes (1MBytes on some MD2 models - two addresses was added VA18 and VA19).
?!!?!
what for ?
MD2 got a special device ?
If I remember the MCD2 could also be connected to a MD1.....

HardWareMan
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Post by HardWareMan » Fri Aug 13, 2010 2:29 am

KanedaFr wrote:
HardWareMan wrote:But, there are not enough address lines on ext port, so you are limited by 256Kbytes (1MBytes on some MD2 models - two addresses was added VA18 and VA19).
?!!?!
what for ?
MD2 got a special device ?
If I remember the MCD2 could also be connected to a MD1.....
I don't think so. Fact remains: some MD2 models/clones got two extra address lines, but I think they not used for compatibility reason. VA18 to B25 pin and VA19 to A2 pin. And don't forget: according to this picture !ROM signal can handle 2MBytes.
Also, those models has two extra sound inputs on ext port: SL3 to B27 and SR3 to A27.

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Post by KanedaFr » Fri Aug 13, 2010 7:22 am

perhaps the MCD2 is faster to transfert data ?
something inside the MCD2 detects if it is connected to a MD1 or a MD2 and so get some steroids :) but I doubt that since we never read stuff like "XXX CD game lags on MD1+MCD2"


[quote="HardWareManAlso, those models has two extra sound inputs on ext port: SL3 to B27 and SR3 to A27.[/quote]

Yeah, I saw...It's been so long I want to play with these SRx/SLx pin...

Just to be sure, what happen if !cart and !fdc ?
Cart is the master and so could access to data throught the external port, right ?
There is now way to access rom data from CD is !cart ?

HardWareMan
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Post by HardWareMan » Fri Aug 13, 2010 8:11 am

KanedaFr wrote:Just to be sure, what happen if !cart and !fdc ?
Cart is the master and so could access to data throught the external port, right ?
There is now way to access rom data from CD is !cart ?
Don't be confused. !cart is an input signal, wich detect insert game cartrige or not (in game cartriges it tied to GND). All it does is swap !ce0 and !rom signals, because if you don't insert any game cartrige, there boot ROM in CD must be mapped to vector area of M68K to able properly boot the system. You can use RAM cartrige with CD (!cart must be leave floating) and got some RAM at $400000-$7FFFFF. And vice versa, you can access to CD boot ROM at $400000..$7FFFFF when use FLASH cartridge. But remember: software in that boot ROM can be compiled to work from $000000 and be not workable at $400000.
As for !fdc signal - it's just a port at $A12000-$A120FF. For CD control registers.

bastien
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Post by bastien » Fri Aug 13, 2010 8:58 am

ok i have finish my excel document,

i want to connect an SMS cartridge slot into a Sega Genesis PCB ,
can you tell me if my redirection is correct ?

please look at this : http://sega4ever.power-heberg.com/tutod ... wiring.xls

or open office if you don't have excel :
http://sega4ever.power-heberg.com/tutod ... wiring.ods

i think i must connect A0 of the SMS slot to +5V and the Reset too, is this correct?

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Post by KanedaFr » Fri Aug 13, 2010 8:59 am

Hmmm....
So, if I don't connect !cart to GND (on cart side), CD will boot and cart data is readable on $400000+
if I don't connect !cart to GND (on cart side) and doesn't connect a CD, nothing happens.
if I connect !cart to GND (on cart side), Cart will be boot and CD is readable at $400000+

I'm not familiar with $A12000-$A120FF, it's where you can switch on/off the led and initiate transfert between MD68k and CD68k right ?
It's too related to CD, not general use...I mean I can't use $A12000-$A120FF to access 'something' else on the ext port

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Post by KanedaFr » Fri Aug 13, 2010 9:10 am

bastien wrote:ok i have finish my excel document,

i want to connect an SMS cartridge slot into a Sega Genesis PCB
Perhaps you'll be interested by
http://devster.monkeeh.com/sega/sega2sms.png

hint : you could add a Pause button on cart :)

bastien
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Post by bastien » Fri Aug 13, 2010 9:50 am

thanks Kaneda but i know it ( i have posted it in my first post),
devster connected a SMS cartrdige in a Meagdrive cartrdige slot, i want to make my own SMS adaptator so i must connect an SMS cartridge slot to a SEGA PCB.

some guys in this forum are knows a lot of things about Genesis so i just wants, they agree my redirection , in the *.xls document ( brr sorry for my english ^^ )

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