Looking for a memory counter rom (NMS8250)

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Por hansgoos

Supporter (10)

Imagen del hansgoos

22-01-2021, 11:49

Hi,

I recently upgraded the RAM of my NMS8250 to 1MB, but the boot screen still shows 128K. I know this is normal and that I must replace the ROM (IC118) for a ROM with a memory counter, the problem is that I don't know where I can find this ROM?

The only one I found on the internet is for a NMS8245 (https://www.msxinfo.net/download/nms8245-original-rom-with-m...)

Thanks
Hans

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Por sdsnatcher73

Paragon (1491)

Imagen del sdsnatcher73

22-01-2021, 12:30

The ROM from the NMS8245 will work fine on the NMS8250

Por Briqunullus

Champion (287)

Imagen del Briqunullus

22-01-2021, 12:46

Thanks. I just changed the subrom in my openMSX configuration. It works. Attention is in the details. Nice.

Por hansgoos

Supporter (10)

Imagen del hansgoos

22-01-2021, 14:29

Just programmed the ROM found on the msxinfo.net site in a W27C512 and replaced IC118 with it. Then nothing is happening, and the MSX won't even boot.

Since the name of the ROM file is: nms8245Systemmemounterfastdisk.rom I tried to place it in IC117 (diskrom) and then the MSX boots normal (still showing 128K of ram), including a working diskdrive.

Por sdsnatcher73

Paragon (1491)

Imagen del sdsnatcher73

22-01-2021, 15:17

Check the contents of the original ROMs. You may have to split the rom you downloaded and put the appropriate part in IC118.

Por Meits

Scribe (6185)

Imagen del Meits

22-01-2021, 16:59

I have this one in my 8250 and 8235 and it works a treat (up to 4096KB).

Por hansgoos

Supporter (10)

Imagen del hansgoos

22-01-2021, 17:25

Thanks for your help.

I did split the 8245 file, and extracted the correct ROM now the start screen is showing

VIDEO RAM: 128Kbytes
USER RAM: 512Kbytes

But I have 1024K installed, so why only 512K is showing?

@Meits: in your picture I see only one line ' MAIN RAM: xxxxx' when using your ROM I have the same output as when I'm using the 8245 ROM (VIDEO RAM / USER RAM)

Por Meits

Scribe (6185)

Imagen del Meits

22-01-2021, 17:34

Same rom in different computer.

Por sdsnatcher73

Paragon (1491)

Imagen del sdsnatcher73

22-01-2021, 20:06

You can try the BIOS files from sd-snatcher/FRS: http://frs.badcoffee.info/tools.html

Look for the MSX2newdrv. This combination has many updates and counts the RAM properly (I tested it on openMSX on a machine with 1024kB memory)

Por hansgoos

Supporter (10)

Imagen del hansgoos

23-01-2021, 09:53

Also the combination of the sub- and BIOS ROM from FRS still gives me the same output on the startup screen.

VIDEO RAM: 128Kbytes
USER RAM: 512Kbytes

The testRAM utility shows a memory mapper of 1024Kb

Por Alexey

Guardian (2982)

Imagen del Alexey

23-01-2021, 12:13

For YIS-503III I made the special subrom with working RAM/VRAM counter and Nyyrikki's effect on the title:

https://youtu.be/qCJwKXcSDD0

Download:
http://podrezov.com/msx2up/yis503iii_msx2sub_special.rom

Use 'call testr' to start the utility from Basic.

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