Gameboy Development Forum

Hello,

I'm having trouble trying to create my first ROM+RAM rom :
I've specified the cartridge type and the ram size in the header,  but, first, on my emulator memory window, I see all the bits of the RAM are set to 1 (RAM full of $FF) with no instruction for it, and, when I try to write a byte in it, it does nothing.

Do I miss something in my code ? Is there a specific method to read/write in cartridge RAM ?

Thanks.

I use WLA and Virtual  Boy Advance by the way.

Here is my code :


;###################### En-Tete #####################################

.ROMDMG
.NAME "RAM"
.CARTRIDGETYPE 8
.COMPUTEGBCHECKSUM
.COMPUTEGBCOMPLEMENTCHECK
.LICENSEECODENEW "17"
.EMPTYFILL $00

.MEMORYMAP
SLOTSIZE $4000
DEFAULTSLOT 0
SLOT 0 $0000
SLOT 1 $4000
.ENDME

.RAMSIZE 2

.ROMBANKSIZE $4000
.ROMBANKS 2

.BANK 0 SLOT 0

.ORG $0100
nop
jp start

.ORG $0104
;Logo Nintendo, obligatoire
.db $CE,$ED,$66,$66,$CC,$0D,$00,$0B,$03,$73,$00,$83,$00,$0C
.db $00,$0D,$00,$08,$11,$1F,$88,$89,$00,$0E,$DC,$CC,$6E,$E6
.db $DD,$DD,$D9,$99,$BB,$BB,$67,$63,$6E,$0E,$EC,$CC,$DD,$DC
.db $99,$9F,$BB,$B9,$33,$3E

;##################################################################
;###################### Programme ###################################

.org $0150
start:
   
    ld    hl,$A000
    ld    a,$48
    ld    (hl),a
loop:   
    nop
    jr    loop


;##################################################################

With this code I'm trying to get the value $48 at the first adress of my RAM ($A000)