Gotcha , the extra data lines are ran through some 74LS257's and combined. I don't have a schematic but it is just about the same as this.

http://sega4ever.power-heberg.com/tutod ... pinout.jpg

Are you able to post a circuit diagram? Just putting resistors in the line might prevent damage but the RC time constant with the resistance and the load capacitance might be too long for it to work at the chosen clock speed, unless you also put a capacitor, something in the range of 10-22pF ...

I asked another board member ( diff. Board) about his use of this chip while he was attempting to make a snes multicart and this was his response.

"idid get it to work.
I conected two switches
one connected to A21 and one connected to A22.
So that every combination would select a part.

A22 - A21 ...

Just thinking out loud here. Maybe the it needs power to select between tr upper and lower banks. I'm not sure.

Another bit of info is it seems that with different variations of power the chip will select differently. Like when I tried the filter. It would select track 4. No filter it would select track 2 , a filter with 2 resistors would select track 3.

I've actually got the setup to select through all of the tracks once. But it wouldn't do it in any order. It would jump around. I don't understand why. Maybe a power surge? That's why I was attempting the low pass filter.

And yes. The reset line was ran to the clock input of the binary counter. I use a 74LS161

Yes. The chip is 3.3v where as the board is 5v. I overcame this by using a voltage reducer. I've got a steady 3.3v to the chip. I also attached resistors to the address lines , not the data lines to reduce them from 4v to 3v.

As far as I know all of the address lines are used. I'm not sure what ...

Ive been attempting to make a SNES cart containing a bunch of classic music. Doing this I need to wire this like it's a multi cart so I can seperate the banks. What I've done in the past is hijack the top 2 address pins of the maskrom and run them through a binary counter. This made it so the ...

Hello everyone. I've got a game i would like to release but would like to install a code to stop people from burning it onto cart. But it would still have to work on emulators. Is there a sequence I can write into the code to help me do this ? I'm referring to a 8 bit NES game.

Sorry , I meant a "save" feature. Damn auto correct. If I have 4 games that all have the save feature. Like zelda , is there a way that all four games could use there own save feature? Right now the SRAM transfers all data from game to game.

Thanks so much !!!


So , if I have it right , if I use a 1mb chip and use Roms that are 128Kb in size each and attach 3 wires iN this order

Pin 1 to q3
Pin 31 to q2
Pin 30 to q1


And it works !! Thanks so much guys.


One more question.

If I want to use 4 games that each have a sac feature ...

I'm not sure if this is in the right section or not. But here goes.

I have been babbling with making a few multi carts for the NES and I have found a tutorial that explains how to make a 4 in 1 cart. But I want to try and make a 8 in 1 or a 16 in 1. I'm not 100% on how the binary counter works ...

I just heard back from the programmer who programmed mario in some usual day. Although its been years since he did that game he had this to say

"Hmm, if I recall correctly when the 'save' is enabled, then the RAM in the range $6000 to $7FFF will automatically be saved. So you need to add a routine ...

Alastair,

Thanks for all of the suggestions. I will do as much as I can. And I agree 100% about learning 6502 Programming. Ive always wanted to but life always seemed to get in the way. Now that Im older I have more patience and time to do the things Ive always wanted to do. And programming my own ...