89s8252 have a 2k on chip eeprom. and have a control bit to direct the movx instruction to this eeprom. can we run rtx-51 full in single 89s8252? since it is require external memory?
For accessing the EEPROM take a look to: http://www.keil.com/support/docs/2369.htm. The RTX51 Tiny will work perfectly on the single chip AT89S8252.