I download programs from a PC to an AT89S53 (very similar to AT89S8252) using the PC serial port. I use a dedicated AT89C2051 to communicate through the RS232 to the PC, and use some 2051 I/O pins to create the SPI link. The PC SW runs under MSDOS.

All this complication is not required if you can use the printer port. In my application the use of the serial port was a must.

In addition the 2051 translates the HEX file it receives from the PC and implements the SPI protocol.

Using the Philips 89C51RD+... you can work in a similar way, but all is included in one chip.

Regards,

Alfredo.