i have one external buffer to store the input values .while processing i need to read the input values from that buffer to my Winbond controller in Port(P0)
how can i read this external buffer?
We do not know what your "external buffer" is.
Is it xdata memory internally to the chip?
Is it xdata memory externally?
Is it eeprom memory connected using I2C?
Is it ...
You really have to supply more information if you want help. The information you give - a Winbond controller connected to P0 - is irrelevant.
It is a XDATA memory externally
and i also want EPROM connected with I2C.
Actually accessing your external xdata memory is identical to accessing internal xdata memory. It's just a question of memory address.
I presume that you mean EEPROM. Look at sample code for I2C communication (either Keil examples available with the compiler, or application notes from your chip manufacturer). Also look at the Code Architect for generating a skeleton code.