Hi guys, just thinking right now how difficult would it be to convert an r4 flashcart to work on a snes, gba, nes, or other eprom based consoles. Is it technically possible?
1. does pinout makes any sense, of course with some rewiring. basically if the processor inside r4 is capable of pulling more lines if needed.
2. bios loader, what's the programming language used for r4? what is required?
this would be a cool project if feasible, most of us had access to an old r4, also very cheap these days.
The logic to handle the DS cart edge protocol is probably more complex than the logic to handle the SD protocol. So the best bet is to take the microSD out of your R4 and put it in a Super EverDrive, SuperCard, or something else that accepts SD or microSD.
You are asking if it is possible to make a SNES flashcard with a DS flashcard , because r4 are cheap these days.
Read your own question and think about it.
actually i opened up a ds flash cart, it contains a controller which is enclosed under a gloptop, but interestingly there is also a flash chip, most probably holding the firmware to boot up, which could be used to also store and play snes games, yet this requires either a special board or good wiring, because it is tsop40/48 (i am not sure, the datasheed refers to both on this part number) and it requires some level shifters, as ds parts run on 3v and the snes supplies 5v on address and databus.
It is not impossible, but it requires either time and/or expensive parts, so i would suggest you get some inl boards instead, as they are cheap, do what they are supposed to do and they are much easier to handle than fiddling around with tiny wires (trust me, i handwired a wiikey fusion to a gc, and it was no fun, because the tiny wires broke of this fcc connector...)
i also made some pictures for those, who want to see whats inside
The TE28F320 is a 2MiWx16bit 3V-only EEPROM. Could be interfaced to a Genesis by adding some voltage shifting ICs. Could be interfaced to a SNES by adding the voltage shifting ICs and either ignoring half the capacity or adding some multiplexers. Would be kinda pointless to interface to the NES because the NES requires extra and widely varying hardware to address more than 32 KiB of memory..
BUT you can also buy new FLASH 'PROMs of the same dimensions, capacity, and voltage for only $1, so I don't see any point in buying an R4 for this purpose.
What is feasible is going the other way around, you could buy a small memory cards, and put PocketNES on it.
I started to experiment with that idea a while back, bought some cheap 16 and 32 MByte microSD cards. I figured it would be possible to change the carts firmware so it just runs the game instead of the menu, but never bothered to try it.
kp64 wrote:
You are asking if it is possible to make a SNES flashcard with a DS flashcard , because r4 are cheap these days.
Read your own question and think about it.
Yes I know What I'm asking, R4 technically could manage to do it, I was talking about rewiring the pinouts to the maskrom and programming a new BIOS. But I didn't have the info on the ICs on the board.
as SNgamer and lidnariq said, it is not impossible. I wanted to see if the pinounts made any logic for a not so time consuming project.
Thanks to SNgamer and lidnariq for your insightful answer. my R4 has custom labeling on the ICs, though my controller is SMD, so I have no idea what is inside of it.
The GBA is a different beast, as if I remember correctly it doesn't have the address and data bus present simultaneously. The address is loaded on one cycle, then data is fetched on the next. This memory might be fuzzy, but I remember seeing that as the solution for re-using the existing cartridge connector shape of the Game Boy while allowing a larger address space.
This document shows how the GBA cartridge connector works.
http://files.darkfader.net/gba/files/cartridge.txt
Summary of protocol: GBA sends a 24-bit word address on A23-A16 and AD15-0 during seek cycles (/CS), then a delay of a couple hundred ns, then the ROM sends one or more consecutive 16-bit words on AD15-0 during read cycles (/RD while +CS2). Reading across 64 Kiword bank boundaries is undefined without another seek.
The random access time is 3.5 GBA cycles at 16.78 MHz, or 208 ns. That's fast enough for PRG ROM on NES, but it might not be reliable for slow ROM on Super NES (which is specified as 200 ns), and definitely not fast ROM on Super NES (120 ns). Sequential access can run faster, but the NES and Super NES cart bus cannot benefit from this.