Have any of you had luck with 35ns OTP EPROMs? I found these two "obsolete" models:

https://www.usbid.com/assets/datasheets/75/m27c4001.pdf
http://pdf.datasheetcatalog.com/datashe ... 081_DS.pdf

I've used Atmel's 45ns OTP ROM in POC V1.1 at 15 MHz. I've not used any ROMs made by ST.

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

Neat! How did you program it?

If I understand right this looks like a 25ns EPROM (though only 2k):
https://media.digikey.com/pdf/Data%20Sh ... 7C245A.pdf

This also got me thinking. 25ns nvSRAM. Not available in DIP but it might be neat with an adapter. Apparently it doesn't need a backup battery:
http://www.cypress.com/file/44406/download

In my TOP853 burner using the AMD 27C256 algorithm. There's nothing special about it.


It is an EPROM, but at only 2K you'll be pretty limited for anything other than a very tightly written boot loader.


It needs an external capacitor to power it during the automatic data store operation. You will need about 22 dollars US to purchase one of these SRAMs. A 45ns OTP ROM is a lot cheaper.

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

If you're after speed, you could go for an F-RAM. I'm under the impression that those are quite fast, and that they come as 5V parallel parts, although the selection among those is limited.
(I have no numbers; I'm working off of memory)

Ya, it is really expensive. I thought it was neat because it doesn't store anything unless you have written at least one byte to it. You could write to it once like an EPROM and then you wouldn't have to worry about store operations unless you wanted to write to it again.

That's interesting. The only 5v DIP parts I have found are 130ns IIRC.

Maybe I'm running off of bad recollections...

I found this one, which is 70ns: http://au.mouser.com/Semiconductors/Memory/F-RAM/_/N-488wv?P=1z0vhtuZ1z0w7ueZ1z0wtznZ1z0wu68&Keyword=F-RAM&FS=True

Oh neat.

I can't find the DIP part I was thinking about.

Apologies on that one, those are SMDs.
Personally, I find SOICs aren't too hard to solder pin-by-pin if you solder the two diagonal pins, and then the rest. Best to use a conical tip for that, though...

Do you mean dead bugging? I've only tried that once with an SMD part but it was pretty tough. I might give it another try for fast memory though.

EDIT: This is what I had found before: https://www.digikey.com/product-detail/en/cypress-semiconductor-corp/FM16W08-PG/FM16W08-PG-ND/4090347
Looks like it is 130ns write time but maybe 70ns for reading.

What's dead bugging? I've never heard of it before.

Turning a chip on its back and gluing it to the board then soldering each leg individually. Some people are really impressive at it but it was pretty darn hard when I tried.

Edit: how do I make the pictures smaller?

Random images from Google:

Ok, no, I was thinking of on a proper pcb, but that is at the top end of the hobby, so...

You can do them about the same way as SOJs. I have my method written up at viewtopic.php?p=48875#p48875, and the picture that goes with them is in BDD's post two posts above it. I don't do one pin at a time.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Ya, I'm not on that level yet. I thought you meant dead bugging since you said pin by pin instead of a bunch at once like Garth was saying.

Garth, that picture looks really good.