Hi Ijaz,

Thank you for joining me again.

I checked (and re-checked for hours :)) ) the voltage levels at the pins themselves. But as you said, without the MCU, some points become floated ones. And even if we pull them up each to 5V by a resistor (10K for example) the results will be always the same; ok for AT89C51, no for AT89S51!

By the way, Pin 18 and 19 oscillate at 8 MHz.

It is amazing that now reading (verifying) an MCU is no more a static procedure as for most memories. But perhaps I am wrong since no one else has experimentally notice it too :)

Kerim