the example: Keil/c51/EXAMPLES/farmemory/16MBRAMonADuC812 I am using ADuC812, if the example can be used with some external Flash Memory,such as W29C040(WINBOND),or AT29C040(ATMEL),or SST29SF040(SST) ?
For what purpose do you want to use the Flash? Program Storage (CODE) or Data Storage (XDATA)?
You may adapt the file XBANKING.A51 so that it writes into Flash. Just take a look to this file.
Note that writing to Flash is not like writing to SRAM: you don't just address a byte & write it - you have to do a whole programming algorithm. And the algorithm may be different for different manufacturers. See the Flash datasheets for details. I think you can implement the algorithm in XBanking so that it looks like a simple write to your 'C' code...?