PROG-GSC V roms

[pierpa86]

Hello guys,
From what I understood by reading all the documentation that I could find around I seem to have understood that it is not possible to set the jumpers to use 8mbit v roms but these must always be 16mbit.
did I get it right ?

 

[twistedsymphony]

PROG GSC can support 16-mbit V-ROMs. AOF2 uses them https://www.mvs-scans.com/index.php/File:Aof_2_set1_b1_front.jpg

 

[pierpa86]

Yes, every game that uses a gsc prog uses 16mbit vroms but is it possible to set the jumpers so that I can use 2*8mbit eproms? From what I've read it seems not
Only SpinMaster uses an 8mbit vrom but because it only occupies the v1

https://www.mvs-scans.com/index.php/Spin_Master

 

[Fluffy]

The pinout of the chips should work with 27c160 style EPROMs, which are 2 Megabyte (or 16 Mega-bit), the chip has a switchable 8/16 bit output, and in this case is hardwired for 8-bit mode. (If you look on the schematic it shows a bridge from GND to /BYTE.)
If you want to use different chips you'll need to check their pinout and possibly make an adapter, and possibly add a decoder.

 

[twistedsymphony]

The pinout of the chips should work with 27c160 style EPROMs, which are 2 Megabyte (or 16 Mega-bit), the chip has a switchable 8/16 bit output, and in this case is hardwired for 8-bit mode. (If you look on the schematic it shows a bridge from GND to /BYTE.)

he's trying to use 27c800 chips for V-Roms on a PROG-GSC board and wants to know the jumper config to do that instead of 27c160s. I'm guessing he said 8mbit instead of 27c800 because he's looking at mask roms.

 

[twistedsymphony]

Looking at games that use this board there are some examples of 8mbit and 4mbit being used, but it's always the last V-ROM. So there are no examples of factory games on this prog board using more than one 8mbit ROM. If you wanted to figure it out you'd have to grab one of these boards and trace out pin 42 one one of the lower V-ROMs

 

[pierpa86]

I converted last resort on proggsc for my collection and i noticed that the audio was audible but some sound was not correct so i understood that no game used the 8mbit mask rom as first v rom.
I solved by adding all the v roms into one 27c160, now the audio is heard correctly.
Thanks for all this informations.

 

[Fluffy]

he's trying to use 27c800 chips for V-Roms on a PROG-GSC board and wants to know the jumper config to do that instead of 27c160s. I'm guessing he said 8mbit instead of 27c800 because he's looking at mask roms.

Ok, I wasn't totally sure which 8mbit is going to be used.
The difference between 27c160 and 27c800 is that pin 42 / A19 is "NC" on the 27c800, so it will be simply ignored. As far as I can see there is no support for multiple 8mbit chips, so it would always need to be the last one. I haven't seen any jumpers to configure V-ROMs when I made the schematic.

 

[pierpa86]

I would also like to express my sincere gratitude for all the information on the neogeo theme that I have been able to read and learn.
twistedsymphony & Fluffy thank you for all the information shared over the years, it has been of great help and interest to me.