6502.org

Darren, go for the AVR. Let us face it, processors are so low cost with bang for the buck these days, it truly makes sense to simply pass commands to a slave processor doing the said chore. For this one test fixture at work, I am planning 7 processors along the chain with the main computer sending out commands along an RS232 and every AT89C2051 responding on an I2C bus. (solonoid driver, AV crosspoint driver, IR port driver and 4 individual IR ports)

Way back in the arcade design days, we used parallel ports which was a pain in the neck if anything went wron with communications.

Funniest was a poker game with 2 65C02s. Main one did the high level language and the second one was the graphics slave. You passed higher level type calls like a GS toolbox setup.

Me likes the I2C nowadays.
Has anyone wrote a 65c02 I2C tool setup?

Lets face it, your graphics board on a pic chip is a huge jump over the past of an entire logic board with RAM and all. Using a pic and memory, it is a design and cost savings.

Still want to see a 65c02 equivalent to an AT89C2051. 2 i/o ports like 65C22, flash programmable and internal emmory and plugs in with a 20 pin DIP.

Well, I'm not using PICs -- I'm using an ATmega32 for the video interface. But, to be honest, let's not forget that one ATmega32 is responsible for 160x100 *monochrome* -- I need another ATmega32 just to handle color, and then I need analog circuitry to produce the proper voltages.

Going back on topic, though, something else you might be interested in using perhaps is the SPI port. That's what I'm using to serialize the video on the microcontrollers, and they support megabits per second if needed.

I2C interface is vaguely similar to the Commodore IEC bus interface. It's pretty slow, but adequate for a lot of needs.

For the work project, I looked into SPI. Quick but extgra lines have some issues. The I2C will do nicely since the programming language I am using is basic to begin with, and the Bascom compiler has command support for I2C as well as SPI. The design just seems to want I2C a tad more...

For a serious and cheap graphics controller, maybe a pic meets a vga chip or some fashion thereof?

Let's nove this to the other thread of discussion. Thanks.

On the topic of ethernet controllers....

I have a SLIP-based TCP/IP stack running (early beta, though) on my GeckOS operating system. I am planning to build a "coprocessor" card for my CS/A65 system with this operating system, and this coprocessor will then do the TCP/IP stack and stuff (another planned purpose would be the filesystem handling for FAT16 on a SCSI disk. Both CPUs (main CS/A65 and copro) are 6502 and running at 1 or 2 MHz. I do have the schematics and even boards already, but not yet assembled and tested.
Both CPUs talk to each other using a shared memory segment (64k). The ethernet connection would either be serial (SLIP, which exists) resp. I am planning on building an ethernet card for my bus system as well. Although I do not yet have the schematics for that yet.

Andre