27C322 to SNES bus?

lunaris · Post by **lunaris** » Wed Dec 09, 2009 9:46 am

Pin 33 - /OE
Pin 24 - /CE

Is /OE the same as /RD?

So in the diagram, do I have the /CE and /OE connections on the LS139 mixed up?

kyuusaku · Post by **kyuusaku** » Wed Dec 09, 2009 1:52 pm

/OE does not go directly to the 245, it goes to the 139. Both of the 245's pin 1 should be grounded--very important!

If you're using something other than a 74LS139, you should tie 139 pins 13,14,15 to +5V as well.

Lastly ROM /CE should be taken from the mask ROM /CE pin hole, because that pin's function never changes, the MAD-1 pins do depending on the board.

If your 245 chips are 74LS, you can tie the EPROM's /CE to 139 pin 1 as well to save a little power.

lunaris · Post by **lunaris** » Wed Dec 09, 2009 10:38 pm

lunaris · Post by **lunaris** » Fri Dec 11, 2009 3:35 am

Also, I did it right down to the last spec with multimeter checked, no shorts or anything and programmed the chip correctly guaranteed. No go, orwannon if you ever read this, since you tested it. Can you check the above schematic and

"For the record, I tied pin 1 of the 139 to pin 4 of the MAD-1. Works like a charm!"

There is no way that can be right... Pin 1 is /CE the MAD-1 Pin 4 links to /OE on HiRom Carts and is not used on LoRom Carts ( I mean the pin 4, not the mad-1 in total ). I even checked with a multimeter, pin 33 on the maskrom (/OE) leads to Mad-1 Pin 4.

orwannon · Post by **orwannon** » Fri Dec 11, 2009 3:57 am

Could it be that you confuse SNES /OE with /CE? There are many docs out there on the net in which these two are mixed up.

Your "corrected" schematic is horribly confusing. Go with the schematic kyuusaku posted (and I quoted) earlier. That'll work.

lunaris · Post by **lunaris** » Fri Dec 11, 2009 3:59 am

I did it orwannon, I even tried to reverse the OE and CE did not work... how did u reply so fast lol? who r u on IRC? lol

edit: my left 3 diagrams of the ICs are the exact same as kyuusaku's. But I did ground and add the +5 connections to the legs not listed (10 is a ground and 20 is a +5V on the 245, and 8 is a gnd while 16 is a +5V on the 139).

Is that correct?

Pin 1 of the 139 is connected to the /CE of the maskrom pin 24, and pin 3 is connected to the /OE (pin 33 of the maskrom).

If both of that is right, I will try editing my VCC and ground such that they all come from seperate wires, because right now, its 1 to the 139, and then they branch out from there for gnd and vcc.

kyuusaku · Post by **kyuusaku** » Fri Dec 11, 2009 9:34 am

I dunno, maybe you have the ROM's endianness backwards, thankfully you can just swap 139 pins 4 and 5.

Oh, what is A0 on the ROM connected to? Sounds like you have those mixed up. ROM A0 should connect to SNES A1, ROM A1 to SNES A2 etc.

lunaris · Post by **lunaris** » Fri Dec 11, 2009 9:52 am

kyuusaku wrote:I dunno, maybe you have the ROM's endianness backwards, thankfully you can just swap 139 pins 4 and 5.

Oh, what is A0 on the ROM connected to? Sounds like you have those mixed up. ROM A0 should connect to SNES A1, ROM A1 to SNES A2 etc.

I checked that, it is wired correctly 100%. I have everything wired as per the diagram I posted above, if that is correct, then my problem lies with my rom or ICs.

Edit: ONE MORE QUESTION

kyuusaku · Post by **kyuusaku** » Fri Dec 11, 2009 10:17 am

If you have thick enough wire it shouldn't matter.

lunaris · Post by **lunaris** » Fri Dec 11, 2009 10:29 am

kyuusaku wrote:If you have thick enough wire it shouldn't matter.

I was using 30AWG, but I have some 22AWG wire. Should I stick to the 30, or move the gnd and +5v to 22AWG wires?

kyuusaku · Post by **kyuusaku** » Fri Dec 11, 2009 11:17 am

30 AWG isn't very good for power, you're limited to about 100mA per tap which I guess could be exceeded. I kind of doubt that's the problem though, more likely it's something logical. Did you try swapping endianness?

lunaris · Post by **lunaris** » Fri Dec 11, 2009 12:11 pm

kyuusaku wrote:30 AWG isn't very good for power, you're limited to about 100mA per tap which I guess could be exceeded. I kind of doubt that's the problem though, more likely it's something logical. Did you try swapping endianness?

I just took the 27c322 out and re-read it... for some reason one of the hex's was wrong.. I had tape on the window by the way.

Willems programmers are a piece of crap lol. 25 degrees celsius, 12.0V VPP, 6.2V VCC +/- 0.25V (I get 0.64 V). Right off the datasheet and these specifications will not work for me with correct jumper settings

... grrr

MottZilla · Post by **MottZilla** » Fri Dec 11, 2009 12:39 pm

I'm not surprised. The older Willems with Jumpers/dip switches and such are crap. MCUMall sells newer USB (no jumpers) programmers and they have 16bit adapters for chips like 27c322. Ofcourse they are more expensive than the average junk willem clone that is parallel port with jumpers and dip switches.

kyuusaku · Post by **kyuusaku** » Fri Dec 11, 2009 1:45 pm

lunaris wrote:I just took the 27c322 out and re-read it... for some reason one of the hex's was wrong.. I had tape on the window by the way.

...But did you swap endianness? The programming software might have chosen little-endian, which would mean you'd have to switch the buffer enables.

lunaris · Post by **lunaris** » Fri Dec 11, 2009 6:54 pm

kyuusaku wrote:
lunaris wrote:I just took the 27c322 out and re-read it... for some reason one of the hex's was wrong.. I had tape on the window by the way.
...But did you swap endianness? The programming software might have chosen little-endian, which would mean you'd have to switch the buffer enables.

no sir, i use the willem software, all i do is select 27c322 and change the jumper settings to what it is listed as + 6.2vcc (@6.4v irl) + 12.0V VPP

what is endian-ness and how would i? is there another common term for it as I have never come across that word?