NeoGeo Blazing Star conversion on PROGTOP board issue, almost there [Solved]

[MagicianLord77]

Hi guys,

I'm trying to do a Blazing Star conversion, and I'm almost there, but don't know how to solve this last issue:

Game animated intro graphics are all wrong, or black, but the gameplay seems to work as it should. Sound/Music is OK too.

First thing I did was checking C roms, my method was zeroing or duplicating some of them in MAME to see if I could replicate the same issue that I have on real hardware. I couldn't.
So just for to see what happens, I halved the SP2 rom (2mb into 1mb+1mb) and made a new SP2 that only has the first part twice, like this:

This, in MAME, made the game work exactly as I have it in hardware. So, I guess the issue is that the upper 1MB from SP2 cannot be addressed and the neogeo receives the lower 1MB again when trying to read it.

Other thing, is that there is no PROGTOP game that uses 1MB SP1 + 2MB SP2, like Blazing Star. So making this work is a bit like uncharted waters, the closest PROGTOP game is Top Hunter, that uses 1MB SP1 + 1MB SP2.
So, maybe the PROGTOP board does not work with 2MB SP2 roms? Why does it say "TC5316200" on its place then?

All eproms I have on the board are 27c322, for P1 and SP2 I just repeat the data until filling the 4MB, altough found for those roms, if I write the data w/o repeating but starting at 0x200000 (2MB) usually works, but I tested both ways in this cart.

I haven't got any other neogeo carts for testing, on this (socketed) PROGTOP + CHA256 combo I've successfully burnt-played-erased:
Robo Army
Andro Dunos
Windjammers
Metal Slug 1
Magical Drop 2
Savage Reign

This is how the boards are at the moment:

In the PROGTOP board, I have jumpers at:
J13 (P1 related)
J5 (SP1 related)
J16, J17 (Vrom related ones)
J7, J10, J1

Although there is no PROGTOP page at neogeodev, PROGBK1 jumpers match pretty well.

Can I do something else to make this work?, thanks!

 

[stj]

i thought if you socketed the roms the boards would not fit close enough to get the cartridge back together??

 

[MagicianLord77]

i thought if you socketed the roms the boards would not fit close enough to get the cartridge back together??

Hehe, you're right, I tried and the cart doesn't close. I just use the pcbs loose, they are held pretty tight when inserted into each socket, I haven't had issues with them falling or anything

 

[MagicianLord77]

Another test:
Removed J7 & J10, jumped J6 & J8, and put P1 rom at P2 place, P2 rom at P1 place

The result is that the game still works, still works the same . Now with P1 and P2 roms switched.

Maybe the game does some kind of bankswitching that only works with PROGBK1?
I think it may be time to get a PROGBK1 board, where can I find the cheapest one? Don't care about the game, don't care about the plastic shell..

 

[nem]

I think it may be time to get a PROGBK1 board, where can I find the cheapest one? Don't care about the game, don't care about the plastic shell..

http://www.jamma-nation-x.com/jammax/mvsboardcodes.html

Not a definitive list, because many games were released on multiple boards. You'll probably want to cross reference with MVS Scans.

 

[MagicianLord77]

I made it work!!

First, PROGTOP board has P1_A19 and P2_A19 addresses tied between. They are enabled with /PORTADRS at the cart edge connector.
But since Top Hunter (the only PROGTOP that uses P2 rom) has only 1MB (A0-A18 (16bit)), P2_A19 is never used, therefore, if it was just grounded, I think it would make no difference.

Blazing Star, and probably every other PROGBK1 game has a different method for accessing P2 second megabyte (A19), this can be seen at the board schematic, highlighted:

We can see that PORTWEL, RESET, and D0 are combined with the help of a 74LS74 to address the 2nd megabyte of P2, this is not shared with P1.

So, I tried lifting the pin of P2_A19 (since I didn't cut the trace at the board yet), and soldering there, very quickly, an old 74LS74 that I had, just like the highlighted part of the schematic, also, a 4.7Kohm resistor between VCC and RESET.

Turned it on and it is a success!

After this, I should solder the chip in a proper way, it won't last long hanging there. Later I guess I could try wiring up the other half of the 74LS74 to make a 4Mb P2 rom possible, also maybe adding another voice rom address to support 4Mb Vroms (PROGTOP supports only up to 2Mb Vroms), and this could essentialy become a PROGBK1 in a PROGTOP.

But now it's time to play Blazing Star lol