And where/why did you get an AT89S8252? They've been discontinued for over a year.

Based on many posts here over the years it seems that there are a lot of unscrupoulous resellers that 'unload' dixcontinued chips on the public.

I have, many times, suggested that anyone, before buying anything, verify that documentation is available. Such an approach would have revelaed that the chip is discontinued. I know many complain about missing support for discontinued items, but, in reality, supporting discontinued items would reduce the support for items not discontinued, which would be far worse.

This lead to another pet peevee of mine which is looking for datsheets in any other place than the manufacturers website. Had the OP looked for the datasheet anywhere else he would not have found the 'discontinued notice'

I can appreciate that some amateurs will go for a bargain, but it is known that "the longest road from a to b is a shortcut you do not know".

So, in conclusion. if an item is discontinued stay away.

I have a couple of thousand discontinued Atmel chips laying in my office and 'could' use them in a limited edition project I am designing, would I? heck no. I will probably use about ten over the next few years to install in a "2 units per year" thingy we sell that was designed with these chips. I guess that, when that item is superseeded I will sell them to a partminer. Partminers are, at least, honest enough to state "we specialize in discontinued chips".

Erik