Read from joypad

homebrew-tutorial/main.asm

@@ -85,23 +85,32 @@ start:
     sta VMDATAL
     stz VMDATAH
 
-    ; write tile 2 to position (4, 8)
-    TILE_X2= 4
-    TILE_Y2= 8
-    ldx #(VRAM_BG1 + (TILE_Y2* 32) + TILE_X2)
-    stx VMADDL
-    lda #$02
-    sta VMDATAL
-    stz VMDATAH
-
     ; Show bg1
     lda #%00000001
     sta TM
 
-
     lda #$0f
     sta INIDISP
 
+    lda #$01
+    sta NMITIMEN
+
+mainloop:
+    lda JOY1H
+    bit #%00000100 ; Down button
+    beq down_not_pressed
+        ; write tile 2 to position (4, 8)
+        TILE_X2= 4
+        TILE_Y2= 8
+        ldx #(VRAM_BG1 + (TILE_Y2* 32) + TILE_X2)
+        stx VMADDL
+        lda #$02
+        sta VMDATAL
+        stz VMDATAH
+    down_not_pressed:
+
+    bra mainloop
+
 busywait:
     bra busywait