Hello Giang Ho,

I think this passage from the original 89S8252's datasheet (http://www.atmel.com/dyn/resou...c0401.pdf), page 23, holds the key to your problem:

The Code and Data memory arrays are mapped via separate address spaces in the
serial programming mode. In the parallel programming mode, the two arrays occupy
one contiguous address space: 0000H to 1FFFH for the Code array and 2000H to
27FFH for the Data array.
 

This indicates that the original source file was designed to assemble into an object file intended for being burnt into the chip using a parallel programmer. Otherwise, there wouldn't be ORG 2000h in your source file.
For parallel programming purposes, the EEPROM appears as part of the target's program memory, at the end of flash. But this ONLY applies to what a parallel programmer sees from the outside while programming is in progress, NOT to what your program experiences (if there is such a thing...) from the inside at run time!!!!!

Your roadmap to a solution:

- Find out if a similar scheme exists for the AT89S8253; if for parallel programming purposes the EPROM is presented as part of code memory under those circumstances. If this is the case, and it may very well be, the address where the EEPROM is presented will almost certainly be different, and probably 03000h.
- If such a scheme dosn't exist in the AT89S8253, you will have to find another way to get your constants into EEPROM at programming time.