M59PW1282 to snes bus?

[klonoa]

Hello everybody.

I want to make a zelda cart with all of the 4 zelda masterquests on it.
My plan was to program the 4 games on a M59PW1282 and use 2 toggle switches on the last adres lines (21,22) to choose witch game to play. Ofcource the M59PW1282 is 16bit so i hooked it up like this: viewtopic.php?f=12&t=4877&start=15
witch has always worked for me. The eeprom works on 3v so i put a voltage regulator between the 5v and eeprom vcc makeing it 3.3 (witch is also fine). I know for sure the games work on the original hardware because i played all of them on a m27c322 devcart that i made.

any words of wisdom for me?

[TmEE]

ESD protection diodes are not going to be happy without bunch of series resistors... unless the chip has got 5V tolerant I/O...

[rkrenicki]

That is an unusual Flash ROM.. Two 64mbit chips stacked on top of each-other by the fab..

Looking at the datasheet, the IO pins have to be +/-0.6v from Vcc unless the operation is less than 20ns at which time it can overshoot to Vcc+2.0v.

[klonoa]

i see.. I just boldly assumed the address lines from the snes weren't such a high voltage.
guess i was wrong i just measured one random address line and it was around 4v.
Does somebody knows how much ohm the resistors must be? I'm not great when it comes to electricity values.

Also do you guys think the chip is busted now? Not that it's a problem i got another 10 of those.
Just a little more work hooking up another tsop chip.

thanks so far guys!

[TmEE]

100....470ohm is useful, I personally use 220

[klonoa]

100....470ohm is useful, I personally use 220

Thanks a lot!
Do you think i should replace the chip?

[TmEE]

if it still works then I would leave it alone.

[klonoa]

hooked up 220ohm resistors to all address lines going to the eeprom and used a new one. No result.
I'll double check the wiring tomorrow,
Should i also hook the 2 245s and the 139 to the 3.3v? (have them on the 5v now.)
seems kinda unnecessary to me looking at the datasheet.
What do you guys think?

Also is there anyone that can verify a M59PW1282 for me?
I have little doubt that the guy where i bought them didn't do a good job. but you never know..

[TmEE]

You need resistors on ALL of the pins (except GND and VCC).

At this point you would want to try with another chip too.

[klonoa]

You need resistors on ALL of the pins (except GND and VCC).

At this point you would want to try with another chip too.

i get why i should do that to all of the adres lines, /ce,/oe etc.
But why would i do that to the data lines?
the voltage on the datalines from the eeprom isn't going to be any more higher than 3v.
just enough so the 245's can register a 1.
There isn't anything going to the eeprom on the datalines.
Am i right?

[TmEE]

Right, you're using buffers there which only listen, so no need for the resistors there...

But the chip does seem dead, unless you got buffers order switched so the SNES won't see the bytes in right order...