video: Added basic lcd control code

diff --git a/src/main.s b/src/main.s
index 96a0a22d2a8ecffeadca5f8686f871a48c8fd188..e36345293ac27e3ff480dceafff045682e1077f4 100644 (file)
--- a/src/main.s
+++ b/src/main.s
@@ -7,12 +7,16 @@
 #include "header.inc"
  
 entry:
+  ; *never* turn off LCD without waiting 
+  ; for vblank!
+  call vblank_wait
 
 main:
 @forever:
   jp @forever 
 
 #include "tiles.inc"
+#include "video.s"
 
 ; fill bank
 .fill 0, 0x7FFF - $

diff --git a/src/video.s b/src/video.s
new file mode 100644 (file)
index 0000000..acbdf93
--- /dev/null
+++ b/src/video.s
@@ -0,0 +1,10 @@
+vblank_wait:
+  ld a, [RLY] 
+  cp a, 144
+  jp c, vblank_wait
+
+  ; turn off lcd 
+  ld a, 0
+  ld [RLCD], a
+
+  ret