Replace N64 cartridges by another system

[Gemelo]

Hi everybody !

I'm currently creating my N64 portable.
For this project, I would like to replace my N64 cartridges by a system where i can use SD cards, CF cards or another removable device.

I've seen Marshallh's project called Flash64 that uses CF card but i can't obtain schematic and uC program for the moment.
I've seen too two projects:
-> YAN64BU (http://www.crazynation.org/N64/yan64bu.htm)
-> PV-Backup (http://n64.icequake.net/mirror/valeryia ... ackup.html)

Somebody has tried these two projects?
Somebody has got any news about Flash64?
Otherwise, are there others open-source projects or methods that i can use please?

[thewise1]

Marshallh's is still in development, the software is tricky for the n64. I'm not sure about the other two though.

[blaze3927]

the "best"/easiest option i could think of would be to look further into the v64 jr. its flaw though is that it stores the game on a ram chip which is only 256mbit or 512mbit. but it does have parallel port interface. so as for getting a n64 to read of a cf/sd card i think that would be the easiest option although it would require quite a bit of trial and errors etc...

[Gemelo]

Hi everybody !

Otherwise, in the N64 cartridges, who is the microcontrollor that contains the ROM?
Because i think that it would be possible to replace this microcontrollor. Do you agree?

[marshallh]

The N64 doesn't access cartridges like any other earlier Cart-based system. CPU has no direct access to the cartridge.

Instead the carts are treated like mass storage (CD, disk drive, etc) and the RCP handles cart reads.

The games are stored on mask ROMs inside the carts, they are different because to reduce pin count, the address and data lines are multiplexed. (Say, to read, you load the high word of the address, latch it in, then load the low address, etc, then you can burst read one word at a time up to 256 words). At which point the address is loaded again and it starts all over.

You can handle the address latching and reading with a few 74 logic chips, but you have to use parallel NOR flash memory. You cannot use NAND (can only be read on a block basis and also is only accessed serially)

Best route is to use an FPGA and some SDRAM. You'll need a lot of experience with either verilog or VHDL if you want to do this, obviously

[blaze3927]

marshallh's knowledge makes my brain explode

have you ever looked inside a v64 jr. marshallh? do you know if its possible to update the ram/rom /i dunno what it is , i know that someone managed to upgrade a 256mbit one to a 512mbit so do you reckon its plausible to get like a 256 megabyte or something going on?

[stuntpenguin007]

yeah Gemelo, your probably not going to be able to build one easily, and all the backup units on the market are pretty big, although neoflash is coming out with one. The project has been on hold for years now, but I think they're making a little progress. From what I understand they just need to fix a few bugs and make a case, then manage to get it on the market.

[Gemelo]

I find in Valeriya's website this pic:


So the ROM (Game) is stored in one of these three components.

I think too that i can use hard drive or cd-rom drive. Here is the pinouts found in pinouts.ru:
_______________________________________
Example: Sony CD-ROM pinout

1 RESET Reset
2 GND Ground
3 DB7 Data Bit 7
4 GND Ground
5 DB6 Data Bit 6
6 GND Ground
7 DB5 Data Bit 5
8 GND Ground
9 DB4 Data Bit 4
10 GND Ground
11 DB3 Data Bit 3
12 GND Ground
13 DB2 Data Bit 2
14 GND Ground
15 DB1 Data Bit 1
16 GND Ground
17 DB0 Data Bit 0
18 GND Ground
19 WE Write Enable
20 GND Ground
21 RE Read Enable
22 GND Ground
23 ACK Data Acknowledge For DMA
24 GND Ground
25 REQ Data Request For DMA
26 GND Ground
27 INT Interrupt
28 GND Ground
29 A1 Address Bit 1
30 GND Ground
31 A0 Address Bit 0
32 GND Ground
33 EN Bus Enable
34 GND Ground
_______________________________________

I can say in this example that:
-> S_DAT is DB0 to DB7
-> /read is RE
-> /write is WE

What do you think?

Edit: What is the role of ALEH et ALEL ?

[blaze3927]

sorry to burst your bubble but I think that a cdrom is the last thing you could use in a n64, look at the doctor v64, that thing was huge, also I don't think the n64 could read straight off an cd because with the doctor v64 they had to have RAM chips inside it as well
so to make myself clear
CD reads sends image to doctor v64 "chips"
doctor v64 "chips" magically transforms into n64 cartridge
n64 reads magic n64 cartridge

[stuntpenguin007]

Are you sure your not just trying to pirate games? A cd drive isn't very portable.

[blaze3927]

if he wanted to "pirate games" he wouldnt be using an n64, it would be cheaper to buy the games almost. plus pc emulators nowadays are ok

[Gemelo]

stuntpenguin007 said:

Are you sure your not just trying to pirate games? A cd drive isn't very portable.

My goal isn't to pirate games.
I would just try to find a method for people (and me) to replace N64 cartridges in the goal to continue playing on N64.

For instance, i find a method to replace my N64 controller by Gamecube controller (a good analog stick with these controllers ) thanks to Micah Dowty's project:
-> Micah Dowty's project: Cube64: http://cia.vc/stats/project/navi-misc/cube64
-> the result of his project with two videos: I have made a prototype : http://platypux.eklablog.com/article-11 ... nique.html

[marshallh]

Maybe this will help you understand.



The Dr. V64 had a CD-ROM drive. It had a 6502 CPU that traversed the CD's file system and loaded the ROM into DRAM.
Once it was in DRAM, a PLD refreshed the DRAM and also handled read requests from the N64.

I'm not sure I can help you much more, you have some gaps in your knowledge you need to fill before you can attempt this project.

[stuntpenguin007]

OK. Just saying, it might be worth it to wait for neoflash to come out with their backup unit because it looks like its nearly cartridge sized and if you were to try build one it would be bulky. Especially with a cd drive, although it would be really cool. Sorry for accusing you of piracy

Also that cube64 thing is really cool. I made one a while back too.

[Gemelo]

Thank you for your information, marshallh !

I find some things about the n64 cartridge's protocol.

I use firstly a program under linux called hexdump and i use this command with a N64 game file
-> hexdump -C "name of the N64 game file" >> FILELOG

Here is an extract of FILELOG:

Code: Select all

00000000  80 37 12 40 00 00 00 0f  80 00 04 00 00 00 14 49  |.7.@...........I|
00000010  9c 66 30 69 80 f2 4a 80  00 00 00 00 00 00 00 00  |.f0i.òJ.........|
00000020  4d 61 72 69 6f 50 61 72  74 79 20 20 20 20 20 20  |MarioParty      |
00000030  20 20 20 20 00 00 00 00  00 00 00 4e 4c 42 50 00  |    .......NLBP.|
00000040  40 80 68 00 40 80 48 00  40 80 58 00 3c 08 a4 70  |@.h.@.H.@.X.<.¤p|
00000050  25 08 00 00 8d 09 00 0c  15 20 00 ed 00 00 00 00  |%........ .í....|

Here is an pic found in YAN64BU website ( http://www.crazynation.org/N64/yan64bu.htm ):

According to marshall's informations and my examples, i can say that:
-> 0x1000 and 0x0000 corresponds to:
00000000 80 37 12 40 00 00 00 0f 80 00 04 00 00 00 14 49 |.7.@...........I|
-> 0x8037 and 0x1240 corresponds to:
00000000 80 37 12 40 00 00 00 0f 80 00 04 00 00 00 14 49 |.7.@...........I|
etc...

Do you agree with these informations?
Are ALEH, ALEL and /READ generated by the N64 console?


stuntpenguin007 said:

OK. Just saying, it might be worth it to wait for neoflash to come out with their backup unit because it looks like its nearly
cartridge sized and if you were to try build one it would be bulky. Especially with a cd drive, although it would be really cool. Sorry
for accusing you of piracy

Also that cube64 thing is really cool. I made one a while back too.

With these informations, i will try to use SD card or another mini-card to program in NOR flash memory:
marshallh said:

You can handle the address latching and reading with a few 74 logic chips, but you have to use parallel NOR flash memory.
You cannot use NAND (can only be read on a block basis and also is only accessed serially)