SD512 RAM Mapper help needed

بواسطة Underscore

Rookie (22)

صورة Underscore

19-11-2019, 14:43


This device just arrived, and I'm trying to boot MSX-DOS from it on a MSX 1 but to no avail.

It came without an SD card, so I'm using my own. It is a 512Mb card that I formatted as FAT16. I copied the required files (a bunch of .COM, .SYS and etc...) from the PC.

I tried several pin combinations and I got the next results:

Pin1 and Pin2 to left or Pin1 to right & pin2 to left: error: diskdriver no found. System halted
Pin1 & Pin2 to right: boots directly to MSX-BASIX.

Also, as soon as I turn on the machine, the SD512 blinks the LED and then turns off.

Is there something I am doing wrong?

Thanks beforehand.

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بواسطة K72itNET

Rookie (19)

صورة K72itNET

19-11-2019, 16:53

For MSX 1 64K have to use a Mapper Expansion of the cartridge for boot SD in FAT16.
For my card is Pin 1 (Right) Pin 2 (right).
In MSX-Basic use command "CALL FDISK" to partition and format the card.
Copy the MSX-DOS2 (Nextor) file to SD.
Try like this

بواسطة Underscore

Rookie (22)

صورة Underscore

24-11-2019, 02:10

Yes, I have Toshiba HX-20, 64K.

Still, I cannot make it to work.
With both pins towards left, I have just a black screen, either with or without SD card on the cartridge.
Also I tried with pre-fomatted, non-formatted SD card as well as no SD card at all. Yet same results.

With Pin 2 to the left leads to "Diskdriver not found. System halted" error.

I noticed how the LED in the cartridge briefly blinks when powering the machine on. Is this a symptom of something?


بواسطة sdsnatcher73

Enlighted (4287)

صورة sdsnatcher73

24-11-2019, 07:56

I think this may be an issue in the SD512 design, if it does not short pins 44 and 46 (SW1 and SW2) your HX20 will not boot (it behaves as if you are trying to insert a cartridge whilst the machine is powered on. This is a protection mechanism not seen in many MSX’s (especially not European ones but many Japanese also don’t have it). My Yamaha machines have it and I know at least some Toshiba’s are known to have this. Every MSX compatible cartridge should short those two pins or it does not strictly adhere to the standards. Whether this is the case for the SD-512 is something the designer/seller should be able to reveal.

بواسطة sd_snatcher

Prophet (3675)

صورة sd_snatcher

24-11-2019, 14:52

Underscore wrote:

With both pins towards left

1) First, prepare your SD card

1a) For a <=2GB card, if you don't want to fiddle with FDISK on theMSX, you can just use the official SD card formatter on Windown/Mac.

1b) Then you must copy at least NEXTOR.SYS and COMMAND2.COM to the cart root folder. You can get them here.

1c) I would also recommend to install the TOOLS.ZIP on the card

2) SD-Mapper switches: On your machine, you need to set both pins to the right (expander=ON, Mapper=ON)