Here are the parts I'm using, and I'll put my issues below.
Also, if someone is willing to help me out on skype, I will send you a board or 2 (as long as shipping isn't ridiculous).
EPROM - 27C322 x1 (32Mb, 16-bit)
SRAM - gm76c88al-15 x1 (8k, or 16k? "It says 65,536 bit, which is 8k, but also says 8,192 words, which is 16k" )
Multiplexer - 74HC257 x2
Decoder - 74HC139 x1
As well as Passives and battery
Problem 1!:
This is what matters the most.
The EPROM I use requires a couple multiplexers since it has a 16-bit output, I hooked them up but I still don't understand how I am going to make use of the full 32 Mbs, since A0 is now being used for the multiplexer input.
And I really need the full 32Mb (4MB) for the ROM hacks, specifically Invictus, and Super DGR World.
I just opened Invictus in a HEX Editor and there is tons of blank values, I assume its something to do with memory mapping.
So how do I access the full 32Mb/4MB with A0 going to my multiplexers?
Also, does the current decoder setup allow me to use the full EPROM?
I included my schematic at the bottom.
Problem 2:
On the Original SMW cart..
Are they diodes zener diodes, or regular diodes? They look like Zener diodes, but they are old parts so I'm not sure.
And is mine a repo, because it uses a 74hc139 instead of the MAD?
Problem 3:
My SRAM chip has 2 chip select pins, one is active low, and the other active high. Are both necessary? Because if I could use the active high, I could remove Q1.
Problem 4:
What pin on the ROM (MX23C4001-12 on the SMW Cart, not my EPROM) is connected to the 1Y0 Decoder pin? When I check with my multi meter its going to pin 31 on the ROM, and some datasheets are saying its A18, and others are saying its A9)
I thought it was supposed to go to the ROM's /OE pin?
This page shows write enable, should I assume the datasheet for those chips are wrong? I couldn't find the MX datasheet, only X23C4000, UMC23C4000/1 and PD23C4001E
Problem 5:
Some Pinouts online say BA5 (pin46) on LoRom is A20, and others say its A21.
Same thing with BA6, some say its A21, some say its A22.
I'm going to assume its the former for both pins, but just want to make sure.
Here is my schematic. I know some of my address lines are wrong. And I'm not sure if the decoder setup allows for full use of the EPROM.
https://i.postimg.cc/JhybGvsM/32-Mb-Lo- ... ematic.png
