Working with HEF

[richard]

Cyls        var     byte
Start:
GOSUB Write_HEF
GOSUB Read_HEF


Write_HEF:
ASM
    BANKSEL PMADRH
    MOVLW    1Fh
    MOVWF   PMADRH                          ;PMADRH = $1F, 1st HEF Address is 1F80h
    MOVLW   80h
    MOVWF   PMADRL                          ;PMADRL = $80
    BCF     PMCON1,CFGS
    BSF     PMCON1,WREN
    BSF     PMCON1,LWLO
    ????  MOVIW   _Cyls  see below
    MOVWF   PMDATL
    
ENDASM
    GOSUB UnlockHef
@   BCF     PMCON1,LWLO
    GOSUB UnlockHef
@   BCF     PMCON1,WREN   
RETURN

What am I missing?

start here I think
1st HEF Address is 0x1F80h not 0x0f80


MOVIW _Cyls
this won't work that's an indirect load of wreg but a fsr has not been loaded or selected

BANKSEL _Cyls
movf _Cyls,w  
BANKSEL PMDATL
movwf PMDATL
clrf      PMDATH  ? ;  a write is 1 word

does writecode not work for these chips ?