131 replies to this topic

[theloon]

Can 2600 games access the save RAM? Since the SaveKey isn't sold anymore it'd be interesting if I could access XM save RAM from batariBASIC.

[GroovyBee]

theloon, on Mon Mar 26, 2012 9:09 AM, said:

Can 2600 games access the save RAM? Since the SaveKey isn't sold anymore it'd be interesting if I could access XM save RAM from batariBASIC.

Its possible but it will need extra work on your part to remain compatible: 7800 games only access the HSC RAM via HSC BIOS calls so they don't access it with direct reads/writes. To be compatible with the BIOS you'd have to reverse engineer the data structures in the HSC RAM. You need to bypass the BIOS because it contains 7800 hardware specific code (I reverse engineered the code for the HSC BIOS a couple of years ago if you look in the 7800 programmers section, but I didn't get very far with commenting it). The HSC RAM occupies a 2K block and is located at 0x1000. That address corresponds to the normal 2600's SARA base address. The HSC RAM is not SARA compatible because it doesn't support the SARA memory access modes.

The SaveKey is easier to get going with in my opinion. There is already some example source code to work with it out on the forums. You need to speak to Richard H about allocating a page or two for your project so that you don't clash with other people. Drop CPUWIZ a PM if you are after one. I'm pretty sure he'll be able to sort you out.

[keitaro]

I'm very interested in this project. but I have some questions about some features described in page 1:

- Hiscore support: I belived this feature was built in the module, while says 'Hiscore cart' I have my doubt now. Is it built-in or includes a separate HS Cart?
- Hiscore support (again): newer games could use HS support for PAL systems, or HSC doesn't work at all in PAL systems?
- (maybe a bit stupid question but I need to confirm it): no aditional power supply is needed to use this module, is right?
- XM games could use Pokey and Yamaha chips at once?
- XM would have his own Bios?

Regards,

[GroovyBee]

keitaro, on Wed Apr 25, 2012 8:25 AM, said:

I'm very interested in this project. but I have some questions about some features described in page 1:

If you decide to purchase an XM there are still some available in the first batch of units at the Legacy Engineer store here :-

http://www.legacyeng...com/storefront/

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- Hiscore support: I belived this feature was built in the module, while says 'Hiscore cart' I have my doubt now. Is it built-in or includes a separate HS Cart?

The HSC capability is completely built into the XM so there is no separate cart. If the XM BIOS detects a CC2, H2 or HSC cart plugged in, it disables its built in HSC to avoid bus/data conflicts.

Quote

- Hiscore support (again): newer games could use HS support for PAL systems, or HSC doesn't work at all in PAL systems?

I did some experiments a while ago and found that many of the PAL versions of the NTSC games that support the HSC crashed or have on screen junk when trying to display HSC information. The original HSC BIOS is not PAL compatible and I have no plans to make it so. If the XM detects a PAL console the XM's built in HSC is always disabled. However, it It can be re-enabled from a BIOS menu option for any homebrew games that work with the HSC in PAL.

Quote

- (maybe a bit stupid question but I need to confirm it): no aditional power supply is needed to use this module, is right?

Correct! No additional power supply is required.

Quote

- XM games could use Pokey and Yamaha chips at once?

Correct! And TIA can be used too.

Quote

- XM would have his own Bios?

Correct! The BIOS does some housekeeping and also has built in self tests that can be activated by the user to make sure that the XM hardware is functioning fine.

[rmaerz]

GroovyBee, on Wed Apr 25, 2012 8:42 AM, said:

keitaro, on Wed Apr 25, 2012 8:25 AM, said:

I'm very interested in this project. but I have some questions about some features described in page 1:

If you decide to purchase an XM there are still some available in the first batch of units at the Legacy Engineer store here :-

http://www.legacyeng...com/storefront/

Are these shipping? I thought they were still working out the bugs...

[GroovyBee]

rmaerz, on Wed Apr 25, 2012 9:20 AM, said:

Are these shipping? I thought they were still working out the bugs...

Not shipping yet. By "they" I assume you mean Curt and I? All I can suggest is that you keep an eye on the XM status thread here.

[keitaro]

Hi
All answered, thanks.
Also thanks for the link, about HSC, for I understand the problem is from original code I guess, but anyway I'm thinking in get it one!

Good luck, you're working hard.