DIY Parodius cartridge

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By SkalTura

Champion (395)

SkalTura's picture

05-12-2022, 11:56

Question...

I tried to make a cartridge for Parodius to play on my MSX1, but it doesn't work at all.
Goes straight to BASIC...

Pretty sure that Parodius is an SCC mapper, so I used this schematic to make the cartridge (think it's from Jipe originally ?)

Only things I did different is that I didn't use the 74LS00 to invert A12 signal, but used one of the free 74LS02 NOR gates to ground to invert A12 signal.
I used an 74LS670 instead of the HC version mentioned in the schematic.
And I used a 29F010 instead of the 27C010.

It should run without having an actual SCC chip, correct ?

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By Wlcracks

Champion (494)

Wlcracks's picture

05-12-2022, 12:41

In WBass you can see with the monitor what is in page 1 of the slot what happens. Maybe doesnt even work for page 1. #4000-#7fff needs to start with #41#42

By Jipe

Paragon (1586)

Jipe's picture

05-12-2022, 15:42

this diagram is just a study for flashroms from a multi mapper with SRAM that I made
I forgot to put the 4.7 K resistors between signals A13 A14 A15 A16 and ground
how do you program the romflash?
do you know this loaders for MSX : https://msxvillage.fr/upload/multiflash.zip
https://msxvillage.fr/forum/topic-1001-8+fabrication-d-une-f...

By SkalTura

Champion (395)

SkalTura's picture

05-12-2022, 21:13

I have a USB programmer I use for all my UV Eproms and EEproms. Worked for all games and bios Eproms so far...

I will add the pull-down resistors and try again.
Thanks

By SkalTura

Champion (395)

SkalTura's picture

08-12-2022, 13:39

Hmmm.... Added the resistors, but still nothing.
Tried it as Konami mapper with Penguin Adventure for MSX1, and as SCC mapper with Parodius for MSX1.
Also tired swapping the OE and CE signals on the 29F010 chip.
Goes straight to Basic every time...

By Jipe

Paragon (1586)

Jipe's picture

08-12-2022, 18:11

i tested don't work with this shematic Sad
no boot
i send you a mail for other solution

By SkalTura

Champion (395)

SkalTura's picture

10-12-2022, 15:21

Jipe wrote:

i send you a mail for other solution

Thank you again very much for your help..!
I just remade the PCB, and this time it works great.

Also tested it with Penguin Adventure, but something strange happened here.
My MSX1 reset itself 2 times before starting the game...?
Didn't do this with the Parodius ROM, that one started first time every time.

Anyway, it works for Parodius, and that was the goal here Wink
Thank you !!

By SkalTura

Champion (395)

SkalTura's picture

22-12-2022, 14:05

So... turns out it doesn't work as expected...

The mapper I ended up making was for a "normal" Konami ROM, and that works fine (for a Konami ROM).
But the modified Parodius ROM only works until you defeat the level 6 end boss. After that the end credit movie should start, but instead, my MSX1 resets itself.

I tried making the SCC mapper differently using another schematic found on a French MSX site, but that one doesn't start either, like the original schematic I had before.
So I tried adding the part from the Konami mapper to the SCC mapper schematic, but then I only get random blocks of color.

Note: I have added decouple capacitors to the actual cartridge, just not drawn in the schematic...

I also tried to trick the cartridge by using the Konami GameMaster 1 cartridge to start Parodius, but that also didn't work

Anyone else have a schematic I can try for a Konami SCC ROM cartridge (without the actual SCC sound chip).
And I would like it to be with traditional logic chips, so no PLD or FPGA chips...

Thank you in advance

By SkalTura

Champion (395)

SkalTura's picture

23-12-2022, 06:03

Did some more testing, and I found something I would have never expected....

My MSX1 is a Philips VG-8020/40, and since this is not standard in BlueMSX, I used my programmer to read out the original system Bios (many years ago).
So today I tested the modded version of Parodius in the BlueMSX's standard VG8020/20 downloaded from the web, and in this model Parodius is not resetting after the lever 6 end boss..?
To be sure, I also tested the modded version in other machines, and it seems that my original Bios is the cause of the problem ???
Going slightly mad, I again read the system Bios with my programmer to check, and compared the files only to find that one single bit was different (for some mysterious reason) oO
Now using the newly read VG8020/40 Bios in BlueMSX, and no more reset after the end boss !!

So I'm going to use the normal Konami mapper with the modded Parodius ROM for my Parodius cartridge.
(thank you Jipe) Cool

But I would still like to have a working version of a SCC mapper, so my question about this still stands Wink

By pakoto

Expert (71)

pakoto's picture

25-12-2022, 20:08

SkalTura wrote:
Jipe wrote:

i send you a mail for other solution

Thank you again very much for your help..!
I just remade the PCB, and this time it works great.

Could you share your working version? Thanks in advance!

By ducasp

Paladin (669)

ducasp's picture

25-12-2022, 20:31

SkalTura wrote:

Did some more testing, and I found something I would have never expected....

My MSX1 is a Philips VG-8020/40, and since this is not standard in BlueMSX, I used my programmer to read out the original system Bios (many years ago).
So today I tested the modded version of Parodius in the BlueMSX's standard VG8020/20 downloaded from the web, and in this model Parodius is not resetting after the lever 6 end boss..?
To be sure, I also tested the modded version in other machines, and it seems that my original Bios is the cause of the problem ???
Going slightly mad, I again read the system Bios with my programmer to check, and compared the files only to find that one single bit was different (for some mysterious reason) oO
Now using the newly read VG8020/40 Bios in BlueMSX, and no more reset after the end boss !!

So I'm going to use the normal Konami mapper with the modded Parodius ROM for my Parodius cartridge.
(thank you Jipe) Cool

But I would still like to have a working version of a SCC mapper, so my question about this still stands Wink

An EPROM usually holds data for something between 12 to 35 years... So, a bit flipping over so many years seems like reasonable Tongue Would never thought about it though, great catch Wink

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