SNES SOP-44 to DIP36

[ichigobankai]

Hi guys,
i've made 2 tiny adapters for my repros,
1st for 29F1610 SOP eeprom (16mbits)
2nd for 29L3211 SOP eeprom (32mbits)



While the 16mbits works perfectly, the 32mbits don't boot (always black screen)
Eeproms are set in 8bit mode (/Byte = GND)

The schematic of the 32mb is based on the 16mb, only 2 minor adds/changes, the vcc is connected to an LM1117 regulator and A20(eeprom) goes to A21 snes (8bit mode)

- I've a stable 3,3v on the eeprom (VCC and /WE).
- 2 games tested, lo & hirom, working properly on 29f032.

If anyone have any idea to make it works...
Thanks !

[TmEE]

I checked your 32MBit Flash datasheet and it is most definitely 5V intolerant. VCC + 0.5V on any input is listed as absolute max.

[ichigobankai]

Yes I know this, but it's working perfectly on any SA-1 repro.

So, i've found something.
The lm1117 takes too much time... with 2x1n4148, games are booting/running fine.

Edit.
With the regulator too !
I must place a capa between output and gnd (10µf)

[Markfrizb]

Yes I know this, but it's working perfectly on any SA-1 repro.

So, i've found something.
The lm1117 takes too much time... with 2x1n4148, games are booting/running fine.

Edit.
With the regulator too !
I must place a capa between output and gnd (10µf)

You should use a 22uf cap tantalum on both input and output for stable regulation.

Using your 32m flash rom in a 5v in/out will cause it to fail quickly. I don't know about the SA-1's I/o's voltages-- maybe they are lower.... But regular carts are 5v.

[getafixx]

Yes I know this, but it's working perfectly on any SA-1 repro.

While it may appear to be working 'perfectly' it is still pushing the chip beyond its tolerance levels, which means the chip will eventually fail.

If you were to incorporate some level shifters into your design that could translate between the 5V and 3.3V logic on the pins then you could use this chip without any problems, AFAIK.

[MottZilla]

I have heard as well that certain 5V intolerant parts will *work* for a period of time before they are damaged and will never work again. If it was truly 5V tolerant, it would say so in the specification/datasheet.

[ichigobankai]

Actually, I'm completely agree with all of you.
(level shifters or simple 100 ohms resistor - like Krikzz with everdrive -)

I'am needed some returns form gamers with SA-1 repros (with games like Mario Rpg or Star Ocean) it could be very interesting.
A friend of mine use 29L3211 and 26L6420 in his arcade repros for at least 2 years (MVS / naomi) without problem (+5v cartridges)

[reimon00]

did you make the 29l3211 work in 8-bit mode?, i´m attempting to make a FFVI english patched on a shvc-1a3m-10 board.

[mmz16x]

hello again ichigobankai was wondering when/if your gonna sell this and whats the news on selling your other retro board stuff thx and look forward to your reply