Hi Maziar,

I think you should be able to use the eeprom SPI code for the low level portion of the interface. Atmel has another apnote regarding using the dataflash with an AVR uC. This apnote (in the dataflash section of their website) gives C code for interfacing the dataflash, but this makes use of the AVR internal SPI port hardware. You ought to be able to use the low level 8052 SPI code as a replacement for the AVR hardware SPI, then use the C code for higher level dataflash interfacing. That's the way I'd start, anyway.

Dennis