"Same question is for the external data memory. After 256 bytes (first 256 bytes accessed on-chip), the external data memory is accessed. What address would be output for the first address of external data

A.- It is 0x0000. But using MOVX instructionsmemory? is it 0x0 or is it 0x100 ?"

Not necessarily, on devices with 256 bytes of ERAM it will be 0x100, on the p89c668 it will be 0x2000.

Erik