Cartridge Device for Oric

This is the right place to discuss on how to implement hardware vsync, adding a VIA or AY chipset, puting multiple roms, or how to design a new flash expansion card.
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kenneth
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Re: Cartridge Device for Oric

Post by kenneth » Sat Mar 01, 2014 12:42 am

I will send a video

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Re: Cartridge Device for Oric

Post by kenneth » Wed Mar 05, 2014 5:34 pm

Last edited by kenneth on Mon Jul 17, 2017 3:07 pm, edited 2 times in total.

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kamelito
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Re: Cartridge Device for Oric

Post by kamelito » Wed Mar 05, 2014 10:07 pm

Impressive, good work.
I didn't read all the thread so I was wondering if you can have multiple games on that cartridge?
Time for miniaturization :)

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Re: Cartridge Device for Oric

Post by metadata » Wed Mar 05, 2014 11:33 pm

really nice :)

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Re: Cartridge Device for Oric

Post by barnsey123 » Thu Mar 06, 2014 12:54 pm

That's really cool. Now you need a menu system and a few more games.
I think this system will be great for people who just want to have a nostalgia blast and don't want to faff about with PC's etc.
Great for shows...

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Re: Cartridge Device for Oric

Post by kenneth » Sun Mar 09, 2014 4:06 pm

@Kamelito:
The contain of the cartridge is (almost) the same as the memory of oric when the game is downloaded from the tape recorder.
I can also load two shorter games files but a menu routine is required.


nota: Diagrams are updated.

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Re: Cartridge Device for Oric

Post by Chema » Tue Mar 11, 2014 1:35 pm

This is really nice!!!! Congratulations.

Let me get a bit off topic now, just for a question. If it is deemed interesting I'd open another thread for this.

I was wondering why not use a similar system to load dumps of games from disk... Some games are not disk compatible. It would be really similar to what you do here, but maybe storing the code not in page 4 but, for instance, in bottom of page 2 if it is not too large.

Maybe even having the code in overlay and just keep in page 2 the disabling of the overlay ram, load of registers and jump to the start address?

Could you tell how you do this?

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Re: Cartridge Device for Oric

Post by kamelito » Tue Mar 11, 2014 3:15 pm

I remember back in the early 80's I went to the home of an Oric owner to copy games (sorry, but I bought some too)
This guy and the same kind of device but he loaded the game then pushed a button and then hit the reset.
Then he was in basic mode and saved the game. It was as I see it a device that poked the right values back to the Oric to remove the protections.

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Re: Cartridge Device for Oric

Post by kenneth » Tue Mar 11, 2014 9:30 pm

@Chema:

I tried to study a pcb with a 27c801 EPROM (1Mo memory like disk) and an octuple register like 74LS273 instead of 74LS74, that could run (Oric regulator will be warmer) but it is necessary to create an other OS and to recode the disk version game.... :shock: :lol:

The cartridge reader works like this:

-The transfert code stored instead "STORE RECALL instructions" is copied in Page 2 after the reset process.
-The transfer code runs, it puts the number of the ROM bank (1/4 of 64K EPROM cartridge) in $3F3 to select the ROM bank, and copy the content in the "same place" in the Oric RAM.
-Then the game starts. (I did it with SkoolDaze :mrgreen: )

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Re: Cartridge Device for Oric

Post by kenneth » Sun Apr 13, 2014 4:53 pm

Here is the final version.
Image

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Re: Cartridge Device for Oric

Post by kenneth » Mon May 26, 2014 7:15 pm


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Re: Cartridge Device for Oric

Post by Chema » Mon May 26, 2014 7:34 pm

Good work!

What I wondered is if it wouldn't be possible to do the same trick for loading from disk those games which are tape based and NOT compatible with disks. That is, they load multiple blocks.

There are many of those out there, such as Defence-Force. Trying to tap2dsk them does not work. However, it shouldn't be impossible to do the same as you do:
1- Load the game in an emulator and obtain a dump of the memory as the load finishes. A snapshot.
2- Get that data into a disk file (some processing maybe+header.exe to generate a tap file+tap2dsk, for instance).
3- Create a loader program that does as you do: load itself into the stack area, for instance, load the dump data into Oric's memory, run the game. Not sure, but I guess you also need to store the register values (including PC to do a JMP there) and maybe other info.

We could have even a menu in the disk to select the game to be loaded.

But, this would be for another thread. Sorry for the off topic, and congratulations indeed for your work!

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Re: Cartridge Device for Oric

Post by kenneth » Tue May 27, 2014 9:06 pm

Indeed, we could create a tap2tap program to convert a "freezed" multi_blocs file to a universal monobloc tape file that we could convert in a disk file but it require to study all the file protections used in the 80's (little bootstrap code in the lower memory etc) to be sure that the main file won't detect the cheat. That could be an interesting tool for Microdisc or Cumulus.

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