Hi everyone,

I have migrated an embedded software from AT89S8252 to AT89S8253. This board will display some characters that people program to EEPROM via RS232 com port by a PC program (written in Delphi and developed by someone else).

The problem I have is that the PC program probably specify to load characters to AT89S8252 memory access at address 2000h - FFFFh, but AT89S8253 has the memory address access at 3000h-FFFFh. Therefore, I could not use that PC program to program to the new AT89S8253. I am thinking to modify the code in RxTx section to write the received data to the

The problem I have is that the PC program probably specify to load characters to AT89S8252 memory access at address 2000h - FFFFh, but AT89S8253 has the memory address access at 3000h-FFFFh. Therefore, I could not use that PC program to program to the new AT89S8253. I am thinking to modify the code in RxTx section (attached) to write the received data (from PC) to the new memory address 1000h above the specified address.

How can I increase the DPTR in this case (DPL, DPH???):
;---------------------------------------------------------------------------------
mov DPL,RxTxStepL ;Load EEProm address to write.
mov DPH,RxTxStepH

mov A,RxTxData ;Load new data

clr EA ;disable Interrupts during write


movx @DPTR,A ;write to EEPROM
;---------------------------------------------------------------------------------
I could post the whole file if neccesary.

Thanks,