There seem to be allot of brand new Atmel 29C256 DIP chips still around.

I'm confused by the other numbers on the chips though and what they mean, if they are relevant or just manufacturing batch numbers or something.

For example, I see AT29C256 12PC, 20PC, 70PI, 90PI, etc.

Does it make a difference? The ones with 90PI after the part number seem to be the newest, am I correct?

Thanks!

Alex

 

 

I'm trying one out now. It has the 90PI designation, but having difficulty in re-flashing it using Moates Burn 2.
Anyone else w issues like this?

 

The designation #'s are the speed and configuration of the chip. The 70XX would be the one to get since its 70 ns access time which has the least likelihood of being problematic. I recall the 90 ns access time chips causing me trouble in the past due to the longer read access time.

 

Ah gotcha, good to know the 70ms is the optimal speed.

Last question then, what would be the difference in the 70PI vs the 70PC?

 

I doubt that these are real Atmel Flash PROMs. Been down this road with these before in the PLCC package (fakes).

As for the designation, the P is for the package type (plastic DIP), the C & I are the temperature ranges. C for commercial (0*C to 75*C), and I for industrial (-40*C to 85*C). Note that 0*C is 32*F, just at the freezing point.

As far as speed, can use chips as slow as 250 nsec access time. So either the 70 (70 nsec) or 90 (90 nsec) chips will work.

RBob.

 

Have a friend checking out the chip I have. He's the one that gave it to me. Keep you posted on what we find.

 

I was afraid of this as well. These new ones are from China. Do you think then it would be a better bet to stick with tested used ones from places other than China?

 

The only new ones I can find for sale from sellers in the US is the 12PC version.

So I know the C tells me it's only a commercial temp range, I presume 12 is the ns access time. What does the P stand for?

 

From post #6, P is the package type. The 12 is for 120 nsec, fast enough for the ECM.

RBob.

 

Gotcha, thanks!