After commenting out a few PORTD & PORTE statements I was able to compile the same 18F452 program for an 18F252. After looking at the EEPROM memory with MPLAB 6.4 I do not see any gaps in the usage. The statements I use in the program to initially set the eeprom are as follows:
DATA @0,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,25
DATA@16,$42,$84,$A4,$83,$01,$24,$C3,$04,$02,$74,$A 3,$44,$C2,$82,$E3,$64,$D4,$43,$03,$81,$23,$14,$63, $94,$B4,$C4
DATA @42,$FD,$7D,$3D,$1D,$0D,$05,$85,$C5,$E5,$F5,$95
I hope this helps?
Dave Purola, N8NTA