Quote from: JoeyBelgier on September 25, 2011, 02:01:33 pm

Hrm, I'd rather want to make a "calculator" with only a d-pad, about 4 buttons and something like MirageOS as -actual- os in stead of a shell. Just for playing games, like some cheap Chinese handheld

hrm

Dpad, four buttons, z80

Didn't nintendo  make one of those things

SEGA did, Game Gear

With this kind of project, you buy a z80. A z80 is just a processor, you need support hardware to make it do things. What good is a cpu without a motherboard, ram, hard drive, ect.

Okay so I was looking at bank switching is it possible to utilize all of the memory, or only the selected memory your using?

The z80 can address 64k of ram at a time. Bank switching divides all the memory into separate chunks. The TI calcs divide it into 16k chunks. You can use all the memory by changing the page that is swapped into a certain part of the 64k address space. If you use 16k chunks, you can access up to 4mb of ram and swap in 4 pages at a time.

You don't need to select them all at once, Keoni. You can switch between them in-program, allowing access to all 64k.

And I still ask: If you're building another calc, why oh why do you want a z80? They're ancient! You can get significantly cheaper, faster, more power efficient CPUs like the cortex M0, which are actually simpler to program Asm for in several ways.