Accesing 512 bit XRAM on P89C51RD2HBP

Its there an easy C way to use the extra RAM on the P89C51RD2HABP??????
Accesing 512 bit XRAM on P89C51RD2HBP

Its there an easy C way to use the extra RAM on the P89C51RD2HABP??????
Uart interrupt, 512 bytes limit???

I have de C51 v4.0. My program implements a uart interrupt (CON1). If in come data stream is 600 bytes, to the Uart, it loss 88 bytes, only de firts 512 bytes are detected; but if then arrived other 600...
Uart interrupt, 512 bytes limit???

I have de C51 v4.0. My program implements a uart interrupt (CON1). If in come data stream is 600 bytes, to the Uart, it loss 88 bytes, only de firts 512 bytes are detected; but if then arrived other 600...
INTERFACE WITH SIMPLETECH FLASH DRIVE SLFLD25R-512

I am trying to interface with SIMPLETECH FLASH DRIVE SLFLD25R-512 with At89S52. But i did git get any succes up till now. Please help me if some sone had this task before.