I've been tracing the Game Genie board (black version) from bootgod's site to see how things connect up. I'm partway done, but it isn't fully-doable because the images are too low-res and also still have the chips in the way. Later this/next week I'll pop open a gold one and take some pictures. I've seen another PCB pic by searching, of a different revision, but no depopulated ones. (Prima facie most of it's the same but less rigidly angled; there's an extra diode...)
One thing that struck me as odd is that the Genie IC doesn't seem to intercept (that is, have different pins for the cart-side and console-side) the CPU data lines, but just connects through a resistor to them. Also that it has some connection to EXP8, though I know not where.
Current findings:
Passed through untouched: /IRQ, EXP0-7,EXP9, PPU/WR, CIRAM /CE, CIRAM A10, all four CIC pins
(Those last six are, of course, each reasons the Game Genie cannot operate solo.)
Passed through, with side-connection(s): CPUA*, CPUD*, CPUR/W, EXP8, PPU /RD, PPUD*
Intercepted: /ROMSEL
yet-to-finish-tracing: GND, SYSCLK, M2, +5V, PPUA*, PPU/A13
I've got a couple questions, some of them for avoiding duplicating work.
(e: yes, I have them layered so things are easily revisable. Layers are awesome. But GIMP xcfs are not on the approved list.)
One thing that struck me as odd is that the Genie IC doesn't seem to intercept (that is, have different pins for the cart-side and console-side) the CPU data lines, but just connects through a resistor to them. Also that it has some connection to EXP8, though I know not where.
Current findings:
Passed through untouched: /IRQ, EXP0-7,EXP9, PPU/WR, CIRAM /CE, CIRAM A10, all four CIC pins
(Those last six are, of course, each reasons the Game Genie cannot operate solo.)
Passed through, with side-connection(s): CPUA*, CPUD*, CPUR/W, EXP8, PPU /RD, PPUD*
Intercepted: /ROMSEL
yet-to-finish-tracing: GND, SYSCLK, M2, +5V, PPUA*, PPU/A13
I've got a couple questions, some of them for avoiding duplicating work.
- How's that work? Does it disable (cartside) /ROMSEL when it realizes it needs to patch after seeing CPUA (and sometimes D), then assert its own? (less important)
- Has someone here already diagrammed the(/a) Game Genie cart?
- Does anyone have images of a depopulated Game Genie corresponding to [url=bootgod.dyndns.org:7777/imagegen.php?ImageID=6848&width=700]this[/url] handy?
- I've noticed a couple of people (Memblers, Blargg) have done mods of their Genies to put in different ROMs. The IMP R1-B001 chip used here is rather hard to find information on, at least in English. (If what I read is correct, they're still available for 1¢/!) To avoid duplicating work...does anyone know the pinout of the R1-B001? (pins 13-17 are d3-7)
- And does socket+ROM fit under the case?
- Or the pinout of the Genie IC?
(e: yes, I have them layered so things are easily revisable. Layers are awesome. But GIMP xcfs are not on the approved list.)