(SNES)Help With Circuit for LoRom M27C322

[Kayumba]

2- What is the transistor ? Is it 2N2222 ?
3- Why do you add switch with JUMPERS, what is those fonction ?

Hey no problem at all man, lidnariq answered the other questions, but I'll answer the rest.

2- I am using the S8050, but any NPN will be fine, could also use an N-channel mosfet as well.
3- The jumpers are solder bridges, so if I don't want to mount the switch, I can just solder one of the connections together.

Good luck with your board!

And if you are using the M27C322, I would make an adapter board as well, it is extremely helpful, I made one on my own with perf board and it was pure hell to solder. Next time I order boards I will definitely be ordering one.

Edit: As for adding HiRom capabilities, instead of having 2 decoders, just add solder bridges to the decoders pins. I just whipped this up quickly, I believe it should work.

HiRomDecoder.png
Hi and Lo Rom Decoder.png



And if you don't want SRAM, just remove battery, SRAM and transistor circuit. Do not even need to make a separate board, just don't place those components. Here is a schematic, you can compare with my original.

LoRom_NoSram.png

Here, if LoROM, I think you forgot to add bridge for pin 15 <-> pin 4


Maybe something like that:


Oh, yeah... You are right here I dont need that:


Its will be better like that:


And all so...
Your "REGLED" net is connected to nothing on your schema.


Normally, pin 48 (BA7) and pin 57 (CPUCLK) of SNES cartridge are dont need to be connected:

[Kayumba]

Given a supercic lock installed into the SNES, "pair mode" on the supercic key lets the game dynamically switch between 50Hz and 60Hz video modes at run-time. I'm really not clear how one would use that.

Why?
If super cic are installed into SNES and on cartridge PCB, its Will not work?

[lidnariq]

Normal operation, with OEM CIC "lock" and "key":
"lock" and "key" have one of two regions, "PAL" and "NTSC". Both must be the same, or the "lock" won't let the SNES boot.

Normal operation, with OEM CIC "lock" and SuperCIC "key":
"lock" has a fixed region. "key" figures out which the "lock" needs so that the SNES will boot.

Normal operation, with SuperCIC "lock" and OEM CIC "key":
"lock" detects what region the "key" wants, and switches the video mode according to the key.

Normal operation, with SuperCIC "lock" and "key":
"lock" detects what region the "key" wants, and switches the video mode according to the key. "Key" always gets success, so always sticks to one region.

SuperCIC pair mode, with SuperCIC "lock" and "key":
"lock" detects pair mode on key. "Lock" treats one one the lines between the two ICs as a digital signal that directly controls whether the S-PPU should run in 50 Hz or 60 Hz mode. I have no idea why this is useful.

[Kayumba]

Normal operation, with OEM CIC "lock" and "key":
"lock" and "key" have one of two regions, "PAL" and "NTSC". Both must be the same, or the "lock" won't let the SNES boot.

Normal operation, with OEM CIC "lock" and SuperCIC "key":
"lock" has a fixed region. "key" figures out which the "lock" needs so that the SNES will boot.

Normal operation, with SuperCIC "lock" and OEM CIC "key":
"lock" detects what region the "key" wants, and switches the video mode according to the key.

Normal operation, with SuperCIC "lock" and "key":
"lock" detects what region the "key" wants, and switches the video mode according to the key. "Key" always gets success, so always sticks to one region.

SuperCIC pair mode, with SuperCIC "lock" and "key":
"lock" detects pair mode on key. "Lock" treats one one the lines between the two ICs as a digital signal that directly controls whether the S-PPU should run in 50 Hz or 60 Hz mode. I have no idea why this is useful.

Sorry , but can you open my mind, please...

OEM CIC "lock" : ?

OEM CIC "key" : ?

SuperCIC "key" : ?
its programmed 12F629 ?

SuperCIC "lock" : ?

SuperCIC pair mode : ?

[Kayumba]

Normal operation, with OEM CIC "lock" and "key":
"lock" and "key" have one of two regions, "PAL" and "NTSC". Both must be the same, or the "lock" won't let the SNES boot.

Normal operation, with OEM CIC "lock" and SuperCIC "key":
"lock" has a fixed region. "key" figures out which the "lock" needs so that the SNES will boot.

Normal operation, with SuperCIC "lock" and OEM CIC "key":
"lock" detects what region the "key" wants, and switches the video mode according to the key.

Normal operation, with SuperCIC "lock" and "key":
"lock" detects what region the "key" wants, and switches the video mode according to the key. "Key" always gets success, so always sticks to one region.

SuperCIC pair mode, with SuperCIC "lock" and "key":
"lock" detects pair mode on key. "Lock" treats one one the lines between the two ICs as a digital signal that directly controls whether the S-PPU should run in 50 Hz or 60 Hz mode. I have no idea why this is useful.

Sorry , but can you open my mind, please...
I still don't understand if it will works if SUPER CIC soldered to PCB and chip installed into SNES ?

OEM CIC "lock" : ?

OEM CIC "key" : ?

SuperCIC "key" : ?
its programmed 12F629 ?

SuperCIC "lock" : ?

SuperCIC pair mode : ?

Lidnariq or thepoorstudenthobbyist, please...
Can you tell me what will be a good solution to make PCB for games with/without SRAM.

What do you think if I will make one bridge for "VCC2" (VCC2 of LittleRain schema) ?
VCC2 will supply : SRAM, Battery, SRAM and transistor circuit from General SNES VCC.
If bridge are connected (soldered), then SRAM, Battery and SRAM transistor circuit are ready to be operating.
Normally 74HC139 are ONLY in use with SRAM and if nothing are plugged to 74HC139 pins, I think it will woks, or no?
Or I do need to do some different connections for 74HC139 when game are LoROM and its without SRAM?
Like here thepoorstudenthobbyist do :


Here, thepoorstudenthobbyist use also "one bridge" when SRAM in use:
https://thepoorstudenthobbyist.com/2020 ... ment-3151

[poorstudenthobbyist]

It's all detailed on my explainer

But if you use a '139 without SRAM, but still wire everything except SRAM /CE to the '139 it'll work.

The "bridge both if no '139" connects the /CART signal to /OE on the EPROM (or multiplexers). But you don't need to (and shouldn't) do that if you have the '139 in the circuit.

The solder pads for the SRAM are only there so you can clear the memory in the SRAM if you want to after installing it. Desoldering the bridge removes power from the SRAM.

[Kayumba]

It's all detailed on my explainer

But if you use a '139 without SRAM, but still wire everything except SRAM /CE to the '139 it'll work.

The "bridge both if no '139" connects the /CART signal to /OE on the EPROM (or multiplexers). But you don't need to (and shouldn't) do that if you have the '139 in the circuit.

The solder pads for the SRAM are only there so you can clear the memory in the SRAM if you want to after installing it. Desoldering the bridge removes power from the SRAM.

Thank you for details.

The "bridge both if no '139" connects the /CART signal to /OE on the EPROM (or multiplexers). But you don't need to (and shouldn't) do that if you have the '139 in the circuit.

Just to be sure that I understand right...
So i can keep exactly the same circuit for 74'139, like this one (LoROM/HiROM) :


Then Create one bridge, for example :


Bridge connects the /CART signal (pin 49) to /OE on the EPROM (pin 13), or multiplexers (pins 15).




So in the case when i making cartridge with a LoROM game that doesn’t save.
And on the board there is : NO SRAM decoder, NO battery, NO 74'139, NO NPN Transistor (with 2 resistors),
I can just solder this bridge to make work LoROM game without saves.


Exact ?

[Kayumba]

Hope that's mean "yes"...
I would like to order first quantity of PCB but want to minimize errors.
Thanks

[poorstudenthobbyist]

HiROM games normally have /CART tied to /OE. Again, you can find all the answers in my explainer, I wrote it specifically for situations like this

Ya know, it took me about five board revisions until I got it totally right and even then I kept modifying the design. I think I'm on my fourteenth at this point.

[Kayumba]

HiROM games normally have /CART tied to /OE. Again, you can find all the answers in my explainer, I wrote it specifically for situations like this

Ya know, it took me about five board revisions until I got it totally right and even then I kept modifying the design. I think I'm on my fourteenth at this point.

to /OE on the EPROM only ?
or it can be tie to /OE of Multiplexers too (pin 15) ?

On your explainer you talk only about ROM’s /OE
"...we just tie the /CART line directly to the ROM’s /OE pin"

[poorstudenthobbyist]

The explainer references a normal SNES cart without 322s. If you read to the bottom, there's a section about bus conflicts that explains the 322 wiring.

[Ice Man]

I have proper 27C322 (27C160 too) adapters for SNES carts made if interested. Took me a few attempts as well because even with the right schematic in mind I accidentally always misconnected /OE. XD

[LittleRain]

Here, if LoROM, I think you forgot to add bridge for pin 15 <-> pin 4

Yes good eye, that wasn't actually a schematic I was using, I just whipped it up in 2 minutes on my current one for an example.

And all so...
Your "REGLED" net is connected to nothing on your schema.

No its not needed, but doesn't affect anything if you remove it.
It was just an old piece I left in, I originally had the LED somewhere else and just never removed it.

Normally, pin 48 (BA7) and pin 57 (CPUCLK) of SNES cartridge are dont need to be connected:

Its not connected to anything, just because there is a wire in the schematic does not mean there is a wire on the board.
Again, it was something I added while creating the schematic, and didn't remove once I was done, since it does not make a difference on the board.