Only flush modified defined characters.

server/drivers/hd44780-low.h

@@ -29,6 +29,14 @@ enum ifWidth { IF_4bit, IF_8bit };
 #define KEYPAD_MAXX 5
 #define KEYPAD_MAXY 11
 
+/* Constants for userdefchar_mode */
+#define NUM_UDCs 8 /* number of characters */
+#define UDCMODE_STANDARD 0 /* only char 0 is used for heartbeat */
+#define UDCMODE_VBAR 1
+#define UDCMODE_HBAR 2
+#define UDCMODE_BIGNUM 3
+#define UDCMODE_BIGCHAR 4
+
 typedef struct ConnectionMapping {
 	char *name;
 	int (*init_fn) (Driver *drvthis);
@@ -48,6 +56,10 @@ typedef struct driver_private_data {
 	// For incremental updates store last lcd contents
 	char *lcd_contents;
 
+	// The defineable characters
+	char *udc_buf;
+	char *udc_dirty;
+
 	// Connection type data
 	int connectiontype_index;
 	struct hwDependentFns *hd44780_functions;
@@ -89,6 +101,8 @@ typedef struct driver_private_data {
 
 	int backlight_bit;
 
+	int udcmode;
+
 } PrivateData;
 
 // Structures holding pointers to HD44780 specific functions