NEO-GEO man
Fake account, shill troll for Christophe Ratel. Us
- Joined
- Aug 26, 2006
- Posts
- 2,050
Yeah i looked at that one, the 42 DIP also only does 16bit.
27C322 as a 32mbit V Rom
- Thread starter Xian Xi
- Start date
bustedstr8
Trollbox Trade Federation,
- Joined
- Oct 15, 2007
- Posts
- 943
Has anyone tried to use a 8bit chip like a 29f032 and do some wire tomfuckery?
Last edited:
Use two 245 chips and one inverter. Map odd byte to one of them, even one to the other, drive A-1 to even bus /OE, /A-1 to even bus /OE.
Should do the trick but it's going to be a big adapter.
Edit:
Checked 257, simpler design indeed, no inverter required.
What you want should looks like this
Could you upload the design again please?
Thanks!
mikejmoffitt
Mickey's Coach
- Joined
- Feb 6, 2014
- Posts
- 578
I did exactly this. I didn't think it through and got a 29F032 burned with the voice roms for Money Idol Exchanger. I hand-wired the entire ROM in there.
What was the high / low byte select on the original ROMs became A0, and the old 16/8-bit ROM's address lines (A0, A1, etc) had to be brought up to the 29F032's A1, A2, etc.
mikey
Marked Wolf
- Joined
- Jun 19, 2012
- Posts
- 215
Made these up a while ago, specifically for repairing V roms that were 32mbit. One is the programming adapter (for use on the GQ-4X, or just manually wire the correct pins for other programmers via the connection points at the bottom of the programming adapter for A19-21) and the other is the adapter for using a 29F032 as an 8-bit 42 pin rom. There are jumpers on the actual adapter, just set them accordingly (middle is mode, jumper to the left for read, and right for programming). Links for OSH Park are below, I've had some made, tested and working. Hope it helps.
Programming Adapter
https://oshpark.com/shared_projects/ep5d2RrF
29F032 Adapter
https://oshpark.com/shared_projects/2b7muPMc
Programming Adapter
https://oshpark.com/shared_projects/ep5d2RrF
29F032 Adapter
https://oshpark.com/shared_projects/2b7muPMc
- Joined
- Dec 1, 2005
- Posts
- 27,753
Noice!!!
- Joined
- Dec 14, 2001
- Posts
- 8,328
I fished this off a boot a long time ago just as a visual chip on 8 bit adapter
I have a bad MS5 Vrom and 1 bad Prom. I used a 322 for the P rom but the v rom is 64mbit so I would need two of these.... I HOPE
I tried using two 322's and one works???
BB
I have a bad MS5 Vrom and 1 bad Prom. I used a 322 for the P rom but the v rom is 64mbit so I would need two of these.... I HOPE
I tried using two 322's and one works???
BB
Last edited:
29f032 its little bit expensive that MX29L3211.
Is possible make an adapter for 4 MX29L3211 with pads for /OE?
mikejmoffitt
Mickey's Coach
- Joined
- Feb 6, 2014
- Posts
- 578
29F032 is a 5V part, while MX29L3211 is a 3.3V part. It is a bad choice; you will either need level transceivers, or you risk damaging the memory and/or the Neo-Geo.
mikey
Marked Wolf
- Joined
- Jun 19, 2012
- Posts
- 215
Anything's possible, but there are issues with what you're suggesting. The physical size of the 29L3211 is much bigger than the 29F032 (it's the same width as my entire adapter board), so making a drop in replacement that will fit in the place of a maskrom is almost impossible. The current design is about the same size as an eprom/maskrom. The power is the other thing, like mikejmoffitt already stated. That, coupled with the fact that a voltage regulator built onto the board would require even more real estate, potentially making the adapter even bigger. Basically, it wouldn't fit anywhere you wanted to use it.
bustedstr8
Trollbox Trade Federation,
- Joined
- Oct 15, 2007
- Posts
- 943
I had to replace a 4MB Vrom recently and used some stuff I had handy.
It's a bit ghetto, but did the trick.
Split the file onto two 27c160 and lift /G on both chips. Hook power and ground onto a 74139 from a convenient spot. Solder a wire into the enable hole where the lifted pin on the eprom would go. Solder eprom 1 with the first 2KB data into the pcb. Flux the legs on the top of the first eprom and push eprom 2 with the second 2KB data onto it, then solder the legs together. Then make the 74139 connections below.
74139:
Pin 1 /G to the enable hole in the pcb
Pin 2-3 Selects to the A20 jumper or to PCM77
Pin 4 Output to /G pin13 on the first 27c160
Pin 7 Output to /G pin 13 on the second 27c160
Depending on the cart and eprom thickness you may need to shave the vent down if it's in the V1 spot.
It's a bit ghetto, but did the trick.
Split the file onto two 27c160 and lift /G on both chips. Hook power and ground onto a 74139 from a convenient spot. Solder a wire into the enable hole where the lifted pin on the eprom would go. Solder eprom 1 with the first 2KB data into the pcb. Flux the legs on the top of the first eprom and push eprom 2 with the second 2KB data onto it, then solder the legs together. Then make the 74139 connections below.
74139:
Pin 1 /G to the enable hole in the pcb
Pin 2-3 Selects to the A20 jumper or to PCM77
Pin 4 Output to /G pin13 on the first 27c160
Pin 7 Output to /G pin 13 on the second 27c160
Depending on the cart and eprom thickness you may need to shave the vent down if it's in the V1 spot.
Last edited:
Yes, but smaller than 4 mask roms.
mikey
Marked Wolf
- Joined
- Jun 19, 2012
- Posts
- 215
I contacted Jian from buyicnow about a year ago, and he said that the 26L6420 with the SOP44 adapter is a drop in replacement for 42 pin, 16bit eproms. It requires 44 pins to program, but just 42 when being read. He is able to program them before shipping as well, which is probably necessary as most hobbyist programmers can't write to a 26L6420. The only issue with the adapter is that it has surface mount pads for the pins. It's possible, but soldering pins for use to replace a maskrom would be annoying, and I'm not sure about the width of the pcb and how it would fit as a drop in replacement. Worth a shot if you want to try it out.
Thanks for your information but if neo geo bus works at 5v this is a bad choice, isn't it?
VI/O PIN OPERATION
MX26L6420 is capable to provide the I/O prower supply
(VI/O) pin to control Input/Output voltage levels of the
device. The data outputs and voltage tolerated at its data
input is determined by the voltage on the VI/O pin. This
device is allows to operate in 1.8V or 3V system as re-
quired.
I have a Last Blade 2 bootleg. It worked fine but next day of playing, the game shows Video Ram error, tried in 3 working Mvs boards and same problem.
Its possible repair it ?
I dont know nothing about making bootlegs. I have a Gq 4x programmer. I have programmed 27c801, 27c1004,27c160 and 322, 29f032 and 016, mxl3211, but this board memories never.
Here a pic of the game board:
Its possible repair it ?
I dont know nothing about making bootlegs. I have a Gq 4x programmer. I have programmed 27c801, 27c1004,27c160 and 322, 29f032 and 016, mxl3211, but this board memories never.
Here a pic of the game board:
Attachments
mbm29f033 has been installer in the adapter, is the same pinout and cheaper.
Unfortunately I cant program it.
This is the configuration:
Name="MBM29F033C*TSOP40",ID="04D4",Class="29F040B",Category="FLASH",MFG="FUJITSU",CodeSize="4194304",DIP="100011110101",Adapter="TSOP40B-DIP32(ADP-077 and ADP-082)";
Any idea?
gq4x dont read the signature id
Unfortunately I cant program it.
This is the configuration:
Name="MBM29F033C*TSOP40",ID="04D4",Class="29F040B",Category="FLASH",MFG="FUJITSU",CodeSize="4194304",DIP="100011110101",Adapter="TSOP40B-DIP32(ADP-077 and ADP-082)";
Any idea?
gq4x dont read the signature id
I have built one recently using 29f032b, I got the adapter to read the chips I pulled from the mvs cart but not the one I made.
I had the same thing happen with snes chips I made but reflowed the solder and 5 out of 6 worked, one of the 29f032b's was dead.
Also my gq4x never read the ID properly, I just turned that off.
If the pinout is the same, try config as amd29f032b tsop 40.
Ill have another go during the week n report back, make sure you have the pins on the chip set to read or write with a blob of solder.
I had the same thing happen with snes chips I made but reflowed the solder and 5 out of 6 worked, one of the 29f032b's was dead.
Also my gq4x never read the ID properly, I just turned that off.
If the pinout is the same, try config as amd29f032b tsop 40.
Ill have another go during the week n report back, make sure you have the pins on the chip set to read or write with a blob of solder.
The flash has been checked and:
Blank check ok
Erase ok
Write failed, Address=0x000000, Buffer=0x08 Device=0xFF
Last edited: