implement timeout in LCD code

lcd.c

@@ -50,6 +50,10 @@
 // !!!!!!!
 
 
+#define T_TIMEOUT (10)
+
+static uint8_t lcd_initialized;
+
 
 static inline uint8_t lcd_read_byte(uint8_t RS)
 {
@@ -79,14 +83,19 @@ static inline uint8_t lcd_read_byte(uint8_t RS)
 }
 
 
-static inline void lcd_wait_while_busy(void)
+static inline int8_t lcd_wait_while_busy(void)
 {
   
   uint8_t byte;
+  uint32_t t_enter = timer_get();
+
   do {
+	if (timer_get() > t_enter + T_TIMEOUT) {
+		return 0;
+	}
     byte = lcd_read_byte(0);
   } while (byte & 0x80);
-  return;
+  return 1;
 }
 
 
@@ -105,46 +114,59 @@ static inline void send_nibble(uint8_t nibble)
   * \param byte The byte to send to the LCD
   * \param RS specifies whether byte sent is data (RS==1) or command (RS==0)
   */
-static inline void lcd_send_byte(uint8_t byte, uint8_t RS)
+static inline int8_t lcd_send_byte(uint8_t byte, uint8_t RS)
 {
-  lcd_wait_while_busy();
-  if (RS)
-    LCD_DATA_MODE();
-  else
-    LCD_CMD_MODE();
+  if (lcd_wait_while_busy() ) {
+	  if (RS)
+		  LCD_DATA_MODE();
+	  else
+		  LCD_CMD_MODE();
 
-  send_nibble(byte >> 4);
-  _NOP();
-  send_nibble(0x0f & byte);
+	  send_nibble(byte >> 4);
+	  _NOP();
+	  send_nibble(0x0f & byte);
+	  return 1;
+  }
+  return 0;
 }
 
 
 int lcd_get(void)
 {
-  lcd_wait_while_busy();
-  return lcd_read_byte(1);
-
+	if ( lcd_wait_while_busy() ) {
+		return lcd_read_byte(1);
+	}
+	return -1;
 }
 
 int lcd_put(char c)
 {
-  lcd_send_byte(c, 1);
-  return 0;
+	if (!lcd_initialized) {
+		return 0;
+	}
+	return lcd_send_byte(c, 1);
 }
 
 void lcd_puts(char *s)
 {
+	if (!lcd_initialized) {
+		return;
+	}
+	
   while (*s) {
     //lcd_put(*s++);
-    lcd_send_byte(*s++, 1);
+	  if (!lcd_send_byte(*s++, 1)) {
+		  return;
+	  }
   }
+  return;
 }
 
 void lcd_cursor(uint8_t blink)
 {
   if (blink) {
     // enable display with cursor + blinking
-    lcd_send_byte(0x0f, 0);
+	lcd_send_byte(0x0f, 0);
   }
   else  {
     // enable display, no cursor, no blinking
@@ -160,6 +182,8 @@ void lcd_init(void)
    * display we be set to 4-bit data mode
    */
   
+	lcd_initialized = 0;
+
   // wait until LCD gets ready to accept instructions.
   timer_wait(50);
 
@@ -189,7 +213,11 @@ void lcd_init(void)
 
   // set to 5 x 8 dots per character,
   // 16 characters per line, 2 lines
-  lcd_send_byte(0x28, 0);
+  int success = lcd_send_byte(0x28, 0);
+
+  if ( !success ) {
+	  return;
+  }
 
   // enable display, no cursor, no blinking
   //lcd_send_byte(0x0c, 0);
@@ -204,6 +232,8 @@ void lcd_init(void)
   
   // clear dislay
   lcd_clear();
+
+  lcd_initialized = 1;
  
   return;
 }