anybody knows the circuit diagram of 892051 using usb port or rs232 port

 

Most of the 892051 programmers on the net are based on 892051, 74373, MAX232 or a couple of transistors. You must be able to get access to a programmer to program the first 892051 before you can use these circuits.

Some of them are here:

http://www.kmitl.ac.th/~kswichit/#2051

You can get USB and RS232 2051 programmer easily from eBay and it has the bonus that you can program 89C51 and 89S51 in the future like this one:

http://www.ebay.com/itm/USB-AT-51-Programmer-89c51-89c52-89s52-89c2051-U36-/200533213642?pt=LH_DefaultDomain_0&hash=item2eb0b601ca#ht_4821wt_832

Allen