Hello sir
My name is RAJESH. I have a small Idea about programming
the 8051 microcontroller. I read all of your articles in freewebs.com
so I want share my ideas with you.
Every one can program the 8051 in ISP mode using RS232 but i have small idea to reduce the space and hard ware we must use USB. Iam sending the circuit to you. just observe and give me suggestions to develop the my project. please sir Iam waiting for your reply.

Thank you by
G.Rajesh
+919966446685
+919490979876

r9966446685@gmail.com

sorry but this is not possible.
reason is USB and RS232 both are different protocols and hence have different voltage levels and communication stuff.

You must need a converter that can make USB to communicate with RS232. I hope you can understand.

Depends on whether ISP is featured or not.For eg Atmel's 89CXX series supports only parallel programming.
The 89SXX series does support ISP but with a synchronous interface(MOSI,MISO,SCK) not the RS232 asynchronous one.
Micros from Philips(NXP) do support programming over the UART.So it seems only these will lend themselves to your application and that too,like Ajay said,with a proper USB to serial converter chip which would allow the creation of a virtual COM port on the PC side.

and for GOD's sake don't start 2 threads for same topic

Arun