PLCC Flash Memory and Adapter

PLCC Flash Memory and Adapter
by Great Hierophant on 2005-07-18 (#2878)

In old prototypes you often see holes broken into the NES casings to accomodate socketed EPROM's, the profile of which was too high to fit into the NES cartridge casing. I don't care for EPROMs for development purposes, I prefer 5-volt Flash Memory. While this may be difficult to find in old-style DIP packaging, it is much easier to find in PLCC packaging. You can get 512 Kilobyte 5-volt PLCC flash very cheaply AM29F040B (Incidentally I believe this type of Flash is also used in PC motherboards. Moreover, its very difficult to break a pin on this type of memory.

So, you have your memory, all you need is an adapter. The adapter on bottom of this page is something like what I had in mind. Two changes would be needed. First, the pinout would need to conform to the NES's custom ROM pinout. Second, the flash holder would have to become more compact, essentially putting the holder in the middle of the DIP package. Otherwise it would overlap with the cartridge pins.

This would be even more ideal for SNES cartridge development, which does not require so many cartridge types for most of the games.

by Memblers on 2005-07-18 (#2886)

Adapter on the bottom of which page? Post the link if you forgot one, I wanna see.

Yep, it seems to be the case that the PLCC 29F040s are cheaper and more common than the DIP ones. I have a PLCC-to-DIP adapter that I got with my EPROM programmer. I ended up ruining a DIP socket by using that with it (it's legs are much thicker than a chip, it loosened up the socket too much).

And yeah, pins on PLCC chips look hard to break, but I managed to do it once so far (IC extractor slip-up). PLCC32 is rectangular, unlike other sizes, so it takes a bit more care perhaps. It still seems easier to insert/remove than DIP though.

by Great Hierophant on 2005-07-19 (#2909)

While PLCC sockets are not zero-insertion-force, gentle prying of the chip will release it from the socket. A gentle push will put it back into the socket. The only difficulty is that AMD Plastic DIP and PLCC chips only reach 512KB, larger sizes come only in surface mounted varieties.

With DIP sockets, you have to put some real force into removing the chip from the socket. To insert the chip, you have to align the chip over the socket carefully or you will bend a pin.

As for burning a Flash chip, I once saw a site that gave instructions to use a (older) PC and a motherboard as a simple burner. Here is an example:
http://evox.xboxhackz.net/evox/guides/b ... chips.html
While the site refers to flashing an Xbox BIOS, the instructions should work just as well for any code you wish to flash onto a chip. Not practical for large scale burning, but should work well for an occassional burn.

The adapters which I referred to are at Sunmark's page
http://www.sunmark.com/
These are not practical for NES cartridges as they are currently designed but could be with a few design differences. They also sell the AM29F040B at a very reasonable $2.95. Otherwise you can find perfecly reusable chips in any motherboard made in the past 10 years.

by Memblers on 2005-07-19 (#2915)

Woah, they sell that little thing for $10 unassembled? Crazyness. Ah well, not like it'd be a massively selling item. The PLCC-to-DIP adapter I use is pictured on here as 'B01': http://sivava.com/
I haven't exactly figured out what the jumper and diodes are for (preventing a backwards insertion from frying maybe?). But it looks the same as the other one, just smaller. But it does have a very high profile (sits over twice as high as a DIP in a socket).

If it's possible though, it would be pretty cool to have a PLCC-to-DIP adapter that could fit inside the cart case. And yeah, with the rewiring being done on the adapter PCB that would be very convenient, that's a pretty cool idea. I'll have to look into it and see if it's possible to make one that small, but I think it could be very difficult for the small size.

by Great Hierophant on 2005-07-20 (#2951)

That adapter was closer to what I had in mind, but the profile would have to be shortened. The PLCC socket is positively cavernous. I think you can get it to be just a little higher than an unsocketed DIP chip with some reworking.

I do note that you are using PLCC flash chips in Squeedo, a very forward thinking move.

by paginate on 2005-08-06 (#3507)

I suck donkey schlongs

by Quietust on 2005-08-06 (#3515)

paginate - piss off, spammer

by Bregalad on 2005-08-06 (#3517)

Oh, that bastard again. I ask myself what's the use of stupidity like this.

by Memblers on 2005-08-06 (#3524)

Alright, heheh I modified the spammer's message to be more accurate and also banned the username. Both their posts were from different IPs though.