PIC30F Data EEPROM reads 0xFFFF first time around - pic

Question

The first time my PIC30F code reads a word from Data EEPROM, it reads 0xFFFF instead of the data actually in EEPROM. It reads fine afterward.
After a bad read, I checked W1 and it does have the correct address
There are no words in data EEPROM with a value of 0xFFFF
I checked the supply: it's 5.13 V
If I break right before the table read instruction, and step through it, it woks fine
I know that NVMADRU and NVMADR are not involved in reading, but I checked them, and their value doesn't change between good reads and bad reads
It's a dsPIC30F5011
I checked the Errata, and did not find any reference to such issue
I am working through the debug function of MPLAB 8, with a PICkit II
I am working through the debug function of MPLAB 8, with a PICkit II: I reset, then run, and it fails
If I place the code in a tight loop until the value is correct, and counting the number of iterations, I see that it takes 2339 times through the loop until it reads correctly
EEPROM read code:
_ReadEEWord:
;--------------------------------------------------------------------------------
; Read a word from Data EEPROM
; Entry W0 Word address relative to the start of Data EEPROM
; Exit W0 Word at that location
; Uses W1, Table pointer
;--------------------------------------------------------------------------------
; Start address of Data EEPROM
#define DATAEE_START 0x7FFC00
; Setup pointer to EEPROM memory
mov #0x7F,W1 ; Set the table pointer
mov W1,TBLPAG ; to the page with the EEPROM
add W0,W0,W0 ; Convert the word address to a byte address
mov #0xFC00,W1 ; Add the start of EEPROM
add W1,W0,W1 ; to the address
nop
nop
nop
; Return the EEPROM data
tblrdl [W1],W0 ; Read the EEPROM data
nop
nop
nop
return
Any suggestions of what may be causing that?

Answer 1

SOLVED
The documentation doesn't say so, but, before you can read data EEPROM, you must wait for any previous EEPROM operations to be done.
You can do it in one of these ways:
1) In C:
#include <libpic30.h> // Includes EEPROM utilities
_wait_eedata(); // Wait for the erase to be done
2) In C, no lib import
while (NVMCONbits.WR);
3) In assembly:
btsc NVMCON,#15 ; If busy (WR bit s set)
bra $-2 ; Go back and wait