void lcd_set_contrast(int val)
 {
-    (void)val;
+  #define PIEZO (*(volatile unsigned long *)(0x7000A000))
+
+  int brightness = val;
+  if ( brightness == MAX_BRIGHTNESS_SETTING ) {
+    brightness = 255;
+  } else
+  if ( brightness == MIN_BRIGHTNESS_SETTING ) {
+    brightness = 0;
+  } else {
+    brightness *= 10;
+  }
+
+  brightness = ((0xff - brightness) << 16) | 0x80000000;
+  PIEZO = brightness;
 }