Vhd interface for victor hc90/95

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By sdsnatcher73

Prophet (3397)

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18-06-2022, 18:41

That may also explain the weird start address, could be RUN in BASIC that is executed… (probably not though)

By popolon_

Champion (287)

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18-06-2022, 18:49

I did not spot any clear basic commands in the binary except these _VP commands.

By popolon_

Champion (287)

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18-06-2022, 19:42

now i managed to made those .bas and binary files, and those loaded in real hc-95. So now i do not have to anymore use the original cassette when testing in real hc-95. Also testing is faster.

By sdsnatcher73

Prophet (3397)

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18-06-2022, 20:15

Great!

By popolon_

Champion (287)

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18-06-2022, 21:12

I now tried all those _vp variant commands, but no signal was get out from card (pins 4,8,10,12). Pin 3 is input so i did not log that . So either the card needs to have all those pins connected and card needs to receive correct data from vhd player before it will send commands towards vhd player. Or something is broken in the card.
I checked briefly that proper clock signal is there for 80C49C.
by the way, this _vp command is not checking the string given at all when giving one parameter in parenthesis, e.g. _vp("22222").
but it will check it when try to give that two parameter alternative (for reading some value from player, e.g. track):
e.g. _vp("g",T) so it does not allow _vp("gg",T)

I will assume that this card would implement these _vp commands, but is missing that VHD interpreter part. Intepreter would be needed to load program code directly from vhd disk and execute it. But is there really own command language in those vhd disk, is it a fact known? Or are those just these _vp / _superimpose commands?

By leonlas

Expert (109)

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25-06-2022, 14:09

Hi.
I'm trying to make this module. I have all the components of the chips except the connector. Do you have a PCB made - project, tested?

By popolon_

Champion (287)

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25-06-2022, 20:06

I have only schematics drawn, i do not have pcb designed for it yet. Pcb is now low priority. After the connection cable between the card and vhd player is resolved, only after that i could make that pcb.
But even with pcb ready and all the components, the rom content from 80c49c (has that 2k rom) must be dumped also, otherwise the card would not work. and then equivalent cpu for 80c49 would have to used, and program that cpu with that rom code.
I am going to try to dump the 80c49c rom content, with this https://www.mattmillman.com/projects/hveprom-project/an-easy.... But i have to first test the dumping with Sharp X1 keyboard ic 80c49 first, or get somewhere cheap 80c49 ic to test.
Meanwhile i made somekind of scart+3x rca+din-8 adapter for that hc9x db25 connector (as the default video input source is that video in from that db25):
https://github.com/popolonx/MSX_STUFF/tree/main/victor_hc9x_...

By leonlas

Expert (109)

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26-06-2022, 02:24

hymmm, I was convinced that 80c49c was equal to 80c49 = https://www.alldatasheet.com/datasheet-pdf/pdf/119046/TOSHIB... and it doesn't need to be programmed

By popolon_

Champion (287)

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26-06-2022, 09:29

80c49C really has internal 2k mask rom (80c39 would be the one without no mask rom). There is no external rom for it. The 32K rom in pcb is only for hc9x computer side, and contains Msx basic extension command _VP.

By popolon_

Champion (287)

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26-06-2022, 11:46

In the thunder storm vhd disk leaflet, there seems to be those different frame numbers (frames from and to) shown for different stages (and opening and game over screen)

IMG_20220626_1242112972.jpg

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