ROM/RAM Cart

Talk about programming CreatiVision (except games programming). Projects of homebrew hardware are also welcome.
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Scouter3d
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ROM/RAM Cart

Post by Scouter3d » Wed Jan 01, 2014 11:46 am

Hi,

I have created a schematic for a CreatiVision ROM/RAM cartridge...

For use with the new Basic or Future Games...

Features:
32Kb ROM plus 32Kb SRAM oboard
switchable between 32Kb ROM + 10Kb RAM (upper memory) or 16Kb ROM + 16Kb RAM(instead of ROM) + 10Kb RAM (upper Memory)

The 10Kb RAM can be changed to 14Kb if no I/O Interface is connected (should only require to Change one "OR" to an "AND")

As i am in no way a pro in building such circuits, i om open to all suggestions/corrections and so on...

PS: Using only a slighly altered Version of this Schematic one should be able to use 46Kb ROM (32Kb + 14Kb upper Memory also as ROM)

Greetings and Happy New Year! TOM:0)
sram_switchable.gif
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Scouter3d
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Re: ROM/RAM Cart

Post by Scouter3d » Mon Jan 06, 2014 3:01 pm

Hi,

I worked a Little on the circuit and was able to reduce one chip...

new schematic attached...

PS: this 12K RAM Version does not work together with the I/O interface

TOM:0)
sram_switchable_4.gif
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@username@
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Re: ROM/RAM Cart

Post by @username@ » Mon Jan 06, 2014 3:17 pm

Forgive me here, I'm obviously missing the point.

If you are designing a new cartridge from scratch, why does it need a ROM?

Is it not possible to do the same as the Harmony cartridge for 2600 and use SD instead?

It simply copies an image from SD and stores it on the RAM to present to the 2600. With simple configs you could manage what is seen as ROM and what is seen as RAM etc.

You can read, download the software (including a menu based fw) from http://harmony.atariage.com/

This kind of cartridge would at least encourage homebrew, as it becomes a quick copy and test cycle.
˙uʍop-ǝpısdn sı ɹoʇıuoɯ ɹnoʎ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı

The creatiVision Emulator 16.04.24
Salora Manager / Laser 2001 BLOAD utility 0.9
CSL Cartridge middleware
http://sourceforge.net/projects/creativisionemulator
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Scouter3d
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Re: ROM/RAM Cart

Post by Scouter3d » Mon Jan 06, 2014 4:52 pm

Hi @username@,

You are absolutly right!

A Cartridge with SD, Software menu to pick an Image and additional RAM would be great!

The simple reason for my Little project is, that such a cartridge is simply to complex for me to build/design... (i am a mechanical engineer with only very limited electronic knowledge...) but i am learning a lot about the CV (and electronics) building this rather simple cart...

Nonetheless on my other thread (Cart for homebrews) i am working on a SD Card solution (using an Atmega chip to read the SD Card and copy the image to SRAM...)
find my Progress here: viewtopic.php?f=13&t=103
Still working on it...

Greetings TOM:0)
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Re: ROM/RAM Cart

Post by @username@ » Mon Jan 06, 2014 8:37 pm

Hey, learning is good, and at the end of the day, helps everyone!

The Harmony Cartridge using ARM7 is overkill - but does the job.

My two cents, this project may be enhanced by also allowing the ROM space to move above $C000.

BASIC 82/83 will most likely not use any more than 8k of RAM, due to it's own restrictions (A-Z and A$-Z$ is all you have for example).

Perhaps porting the Laser 2001 / Salora BASIC would be a better idea, and give more 'bang for the buck' to your project, as you could perhaps do a mini conversion.

On a side note, I do have some experience with SD, USB etc on embedded systems, so software wise, I'm happy to help.
˙uʍop-ǝpısdn sı ɹoʇıuoɯ ɹnoʎ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı

The creatiVision Emulator 16.04.24
Salora Manager / Laser 2001 BLOAD utility 0.9
CSL Cartridge middleware
http://sourceforge.net/projects/creativisionemulator
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Scouter3d
Posts: 372
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Re: ROM/RAM Cart

Post by Scouter3d » Tue Jan 07, 2014 9:38 am

@username@ wrote:Hey, learning is good, and at the end of the day, helps everyone!

The Harmony Cartridge using ARM7 is overkill - but does the job.

My two cents, this project may be enhanced by also allowing the ROM space to move above $C000.

BASIC 82/83 will most likely not use any more than 8k of RAM, due to it's own restrictions (A-Z and A$-Z$ is all you have for example).

Perhaps porting the Laser 2001 / Salora BASIC would be a better idea, and give more 'bang for the buck' to your project, as you could perhaps do a mini conversion.

On a side note, I do have some experience with SD, USB etc on embedded systems, so software wise, I'm happy to help.
Hi,
Yes, allowing ROM above $C000 is easy...
And Yes! porting the Laser 2001 / Salora Manager Basic would be perfect! (i can help with the Hardware, or try to "extract the bios as you metioned over centronics or so...)

A nearly full "conversion" of the CV to a Laser 2001 should be possible (adding 16K of RAM, new BASIC...) i am not sure, where the "additional to the CV" 16K RAM in the Laser are located ($C000? i would guess)

Greetings TOM:0)

PS: Thanks for offering your help! I will come back to you...
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Re: ROM/RAM Cart

Post by Scouter3d » Tue Jan 07, 2014 10:12 am

Hi,

Searching the web (Google is your friend ;0)) i found a few pieces of Information about the Salora Manager/Laser 2001:

http://mamedev.org/source/src/mess/driv ... ion.c.html

Seems the Manager has 16kb ROM (2x8kb) located at $C000 and the two Cartridge ROM Banks on the CV are RAMbanks in the Manager (16kb Standard, 16Kb with the exp. cartridge)...
This Ram must be switched of somehow, when a game cart is inserted...

More to come...

TOM:0)
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Re: ROM/RAM Cart

Post by @username@ » Tue Jan 07, 2014 11:14 am

Hi Scouter3D,

Yes indeed - where would we be without google! I note you say it has a centronics ports too - which means dumping / copying the rom should be straight forward. Be really cool to get both BASIC and the ROM from that machine to work out the differences. As the Laser and Salora have tape loading - homebrew should be just a case of working out the load format!

Thanks for looking into this, if you need me to knock up the capture side for PC printer port, let me know.
˙uʍop-ǝpısdn sı ɹoʇıuoɯ ɹnoʎ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı

The creatiVision Emulator 16.04.24
Salora Manager / Laser 2001 BLOAD utility 0.9
CSL Cartridge middleware
http://sourceforge.net/projects/creativisionemulator
User avatar
Scouter3d
Posts: 372
Joined: Mon Jun 28, 2010 7:02 am
Location: Wien
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Re: ROM/RAM Cart

Post by Scouter3d » Tue Jan 07, 2014 11:52 am

@username@ wrote:thanks for looking into this, if you need me to knock up the capture side for PC printer port, let me know.
Hi, yes that would be great!
I am not sure if the Manger can send all 255 characters, Need to work that out (also the pinout for the centronics and how to access it... or maybe just LPRINT should work...)
On the CV there was a small Programm in the Wizzdom Newsletter, that allowed printing of all characters...

PS: I opend up my Salora (as far as i dared...) => no Chance in desoldering the ROM because of obstrusive daughterboard... (and Chance of ruining everything ;0))

Here are a few Pictures:
IMG_1458.jpg
IMG_1454.jpg
IMG_1448.jpg
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