From 2f5451d76eebb39c0255c496e6eea60a2fda4ae1 Mon Sep 17 00:00:00 2001
From: Silver Kits <silver.kits@eesti.ee>
Date: Tue, 4 Oct 2016 22:00:20 +0300
Subject: [PATCH] Amend lcd_goto() to be safe and not move cursor outside of
 screen limits and add screen positions definitions

---
 lib/hd44780_111/hd44780.c | 4 ++++
 lib/hd44780_111/hd44780.h | 8 ++++++++
 2 files changed, 12 insertions(+)

diff --git a/lib/hd44780_111/hd44780.c b/lib/hd44780_111/hd44780.c
index d0db4bd..d00deae 100755
--- a/lib/hd44780_111/hd44780.c
+++ b/lib/hd44780_111/hd44780.c
@@ -7,6 +7,8 @@ Version:   1.11
 #include <avr/pgmspace.h>
 #include <avr/sfr_defs.h>
 #include <inttypes.h>
+#define __ASSERT_USE_STDERR
+#include <assert.h>
 #include "hd44780.h"
 #include "hd44780_settings.h"
 
@@ -495,6 +497,8 @@ Returns:  none
 *************************************************************************/
 void lcd_goto(uint8_t pos)
   {
+    //Do not go outside of screen limits
+    assert(pos < LCD_COLS_MAX);
     lcd_command((1<<LCD_DDRAM)+pos);
   }
 
diff --git a/lib/hd44780_111/hd44780.h b/lib/hd44780_111/hd44780.h
index dc07d67..19b47de 100755
--- a/lib/hd44780_111/hd44780.h
+++ b/lib/hd44780_111/hd44780.h
@@ -36,6 +36,14 @@ Version:   1.11
 
 #define LCD_BUSY                7    // DB7: LCD is busy
 
+// LCD columns and rows definitions
+#define LCD_ROW_1               0
+#define LCD_ROW_2               64
+#define LCD_COLS_MAX            128
+
+// Maximum character what can be displayed with 1 byte
+#define MAX_CARACTER            255
+
 
 void lcd_init();
 void lcd_command(uint8_t cmd);