Sunrise CF mapper

By gdx

Enlighted (5694)

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13-08-2022, 09:48

Hello,

Some time ago, I wanted to create patches for the Sunrise CF interface but, while doing this, I realized that the emulators reproduce the mapper of the Sunrise CF badly. So I am looking for detailed information about this mapper. Anyone have this information?

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By Manuel

Ascended (18940)

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13-08-2022, 10:06

What is wrong with the emulation? I mean, how did you get to that conclusion?

By gdx

Enlighted (5694)

gdx's picture

13-08-2022, 13:08

I inserted a routine in some places in the firmware that I thought were empty. It is executed as expected by OpenMSX but not on my real Sunrise CF. I suspect area that at least mirrors for data backup are not emulated, or even, that the emulation of the selection of this aera which is buggy or uncomplete.

By Helix

Supporter (1)

Helix's picture

14-08-2022, 01:52

Hi gdx,

which 'places in the firmware' did you try to use? The apparently unused flashrom region 0x7C00-7EFF is mapped away to make the external IDE registers visible. This could already be the case after poweron (random state). So this region can't be used for boot code without clearing bit0 of the flashrom mapper register 0x4104. Your emulator might always start with this bit at zero. That would explain why you see a difference between real world and emulation (if you didn't take proper care of 0x4104).

Some information can be found here:
https://www.msx.ch/sunformsx/download/idetxt/idetech.html

The above info pertains to the original cartridges where a 128kbit flashrom chip was used. I believe Sunrise also produced batches with bigger flash chips where more than 3 mapper register bits were used (presumably bit 4,3,...)

By gdx

Enlighted (5694)

gdx's picture

14-08-2022, 11:15

Thank you, I will try it as soon as i can.

By Manuel

Ascended (18940)

Manuel's picture

20-08-2022, 16:53

Solved?