From 04be2b85da70423d1f882cefdd5f3dd334537892 Mon Sep 17 00:00:00 2001
From: "Collin J. Doering" <collin.doering@rekahsoft.ca>
Date: Fri, 2 Oct 2015 02:46:23 -0400
Subject: [PATCH] Tested operational 4-bit mode

Cleaned up a few comments and tested and verified operation of 4-bit mode.

Signed-off-by: Collin J. Doering <collin.doering@rekahsoft.ca>
---
 lcdLib.c | 24 +++++++++++-------------
 lcdLib.h | 22 +++++++++++++++++-----
 2 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/lcdLib.c b/lcdLib.c
index 68b0411..607c44a 100644
--- a/lcdLib.c
+++ b/lcdLib.c
@@ -269,24 +269,22 @@ static inline void softwareLCDInitPulse(void) {
 void initLCD (void) {
   enableLCDOutput();
 
-  // Wait minimum 15ms as per datasheet
-  _delay_us(LCD_INIT_DELAY0);
-
+  _delay_us(LCD_INIT_DELAY0); // Wait minimum 15ms as per datasheet
   softwareLCDInitPulse();
-  
-  // Wait minimum 4.1ms as per datasheet
-  _delay_us(LCD_INIT_DELAY1);
-
+  _delay_us(LCD_INIT_DELAY1); // Wait minimum 4.1ms as per datasheet
+  softwareLCDInitPulse();
+  _delay_us(LCD_INIT_DELAY2); // Wait minimum 100us as per datasheet
   softwareLCDInitPulse();
 
-  // Wait minimum 100us as per datasheet
-  _delay_us(LCD_INIT_DELAY2);
-
-  softwareLCDInitPulse();
-
-  // Function set (2 lines with 5x7 dot character font)
+#if defined (FOUR_BIT_MODE) || defined (EIGHT_BIT_ARBITRARY_PIN_MODE)
+  // Function Set (4-bit interface; 2 liens with 5x7 dot character font)
+  writeLCDNibble_(CMD_INIT_FOUR_BIT);
+  writeLCDInstr_(CMD_INIT_FOUR_BIT | (1 << INSTR_FUNC_SET_N));
+#else
+  // Function set (8-bit interface; 2 lines with 5x7 dot character font)
   // RS=RW=0, DBUS=b00111000,0x38
   writeLCDInstr_(INSTR_FUNC_SET | (1 << INSTR_FUNC_SET_DL) | (1 << INSTR_FUNC_SET_N));
+#endif
 
   /* BF now can be checked */
 
diff --git a/lcdLib.h b/lcdLib.h
index 00497f0..ea1b3e9 100644
--- a/lcdLib.h
+++ b/lcdLib.h
@@ -46,7 +46,7 @@
 //#define EIGHT_BIT_ARBITRARY_PIN_MODE
 
 // LCD in 4-bit mode (default is 8 bit mode)
-//#define FOUR_BIT_MODE
+#define FOUR_BIT_MODE
 
 // Mode sanity check
 #if defined (EIGHT_BIT_ARBITRARY_PIN_MODE) && defined (FOUR_BIT_MODE)
@@ -68,9 +68,18 @@
 #define LCD_ENABLE_PORT PORTD
 #define LCD_ENABLE_DDR  DDRD
 
-/* Mode specific settings */
+// Screen characteristics (unused) TODO
+#define LCD_NUMBER_OF_LINES     2
+#define LCD_CHARACTERS_PER_LINE 20
+
+#define LCD_CHARACTER_FONT  
+
+/*
+  Mode specific settings
+*/
+
+/* Default Mode */
 
-// Default Mode
 // LCD data bus PORT, PIN and DDR.
 #define LCD_DBUS_PORT PORTB
 
@@ -81,7 +90,8 @@
 #define LCD_BF        PB7
 
 
-// EIGHT_BIT_ARBITRARY_PIN_MODE specific settings
+/* EIGHT_BIT_ARBITRARY_PIN_MODE specific settings */
+
 #ifdef EIGHT_BIT_ARBITRARY_PIN_MODE
 #define LCD_DBUS0      PB0
 #define LCD_DBUS0_PORT PORTB
@@ -124,7 +134,8 @@
 #define LCD_DBUS7_PIN  PINB
 #endif
 
-// FOUR_BIT_MODE specific settings
+/* FOUR_BIT_MODE specific settings */
+
 #ifdef FOUR_BIT_MODE
 #define LCD_DBUS4      PB4
 #define LCD_DBUS4_PORT PORTB
@@ -170,6 +181,7 @@
 
 // Simple commands with no options
 #define CMD_INIT             0x30
+#define CMD_INIT_FOUR_BIT    0x20
 #define CMD_CLEAR_DISPLAY    0x01
 #define CMD_RETURN_HOME      0x02