Re: [stella] Re: Game developers input wanted for 7800 Ram Cart

Subject: Re: [stella] Re: Game developers input wanted for 7800 Ram Cart
From: Chad Schell <gamer@xxxxxxxxxxx>
Date: Tue, 08 Apr 2003 18:48:44 -0700

Well, thats always nice, but not an absolute requirement. A monitor really
only needs:

1) Some method of interrupting any running software (NMI?). (not 100%
necessary, but certainly handy)

The cartridge does not have access to the NMI, only the standard IRQ line. And of course the other question is what would cause the irq to trigger?

Keep in mind this is essentially a cartridge with a serial port, MMC, and some remappable SRAM/Flash memory. It doesn't modify the 7800, it doesn't have any special access to the 7800.
It doesn't have a processor.

I've clearly bitten off more than I can chew in asking this question. :-P

I was thinking more simply in terms of developers tools. Like possibly the ability to have the serial port interrupt a running program and load a new one. But even that could be tricky as once the 7800 is locked into a mode, nothing but cycling power can bring it out of that mode. So a game running in 2600 mode locks the 7800 in 2600 mode.

Let's narrow this down to a really simple question: Assuming this cart was like an open system that anyone could write code for, where would it be most convenient to have flash memory mapped for development purposes?

Then those with more familiarity with the 6502 than I can write tools for it if desired. I do very little 6502 work - I don't even have an opcode chart or a description of all the instructions.

Chad Schell

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