Added new SerialToLCD user project contributed by Simon Foster.

[pub/lufa.git] / Projects / SerialToLCD / Lib / HD44780.c

diff --git a/Projects/SerialToLCD/Lib/HD44780.c b/Projects/SerialToLCD/Lib/HD44780.c
new file mode 100644 (file)
index 0000000..d67dc6d
--- /dev/null
+++ b/Projects/SerialToLCD/Lib/HD44780.c
@@ -0,0 +1,127 @@
+/*
+             LUFA Library
+     Copyright (C) Dean Camera, 2012.
+
+  dean [at] fourwalledcubicle [dot] com
+           www.lufa-lib.org
+*/
+
+/*
+  Copyright 2012  Dean Camera (dean [at] fourwalledcubicle [dot] com)
+  Copyright 2012  Simon Foster (simon.foster [at] inbox [dot] com)
+
+  Permission to use, copy, modify, distribute, and sell this
+  software and its documentation for any purpose is hereby granted
+  without fee, provided that the above copyright notice appear in
+  all copies and that both that the copyright notice and this
+  permission notice and warranty disclaimer appear in supporting
+  documentation, and that the name of the author not be used in
+  advertising or publicity pertaining to distribution of the
+  software without specific, written prior permission.
+
+  The author disclaim all warranties with regard to this
+  software, including all implied warranties of merchantability
+  and fitness.  In no event shall the author be liable for any
+  special, indirect or consequential damages or any damages
+  whatsoever resulting from loss of use, data or profits, whether
+  in an action of contract, negligence or other tortious action,
+  arising out of or in connection with the use or performance of
+  this software.
+*/
+
+#include "HD44780.h"
+
+static void HD44780_WriteNibble(const uint8_t nib)
+{
+       /* Read PORTD and clear the ENABLE and PD0..3 bits 
+          then OR in the data */
+       
+       PORTD = (PORTD & ~(ENABLE | LO4_MASK)) | (nib & LO4_MASK);
+       
+       /* Enforce address setup time (tAS) 60ns 
+          60 @ 16MHz = <1  
+          Let's us a few NOPs for good measure */
+       asm volatile("nop\n\t"
+                    "nop\n\t"
+                    :: );
+       
+       /* Take enable high and enforce Enable High time (tEH=450ns)
+          450ns @ 16MHz = 7.2 => 7 NOPs */
+          
+       PORTD |= ENABLE;
+
+       asm volatile("nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    :: );
+
+       /* Take enable low and enforce Enable Low time (tEL=500ns)
+          500ns @ 16MHz = 8.0 => 7 NOPs */
+       PORTD &= ~ENABLE;
+       
+       asm volatile("nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    "nop\n\t"
+                    :: );
+}
+
+static void HD44780_WriteByte(const uint8_t c)
+{
+       HD44780_WriteNibble(HI4(c));
+       HD44780_WriteNibble(LO4(c));
+}
+
+static void HD44780_PowerUp4Bit(void)
+{
+       /*  Wait for more than 40 ms after VCC rises to 2.7 V */
+       _delay_ms(40);
+       HD44780_WriteNibble(0x03);        // FN_SET 8-bit
+
+       /*  Wait for more than 4.1 ms */
+       _delay_ms(5);
+       HD44780_WriteNibble(0x03);        // FN_SET 8-bit
+       
+       /* Wait for more than 100 µs */
+       _delay_us(100);
+       HD44780_WriteNibble(0x03);        // FN_SET 8-bit
+       
+       /*  From now on we must allow 40us for each command */
+       _delay_us(50);
+       HD44780_WriteNibble(0x02);        // FN_SET 4-bit
+
+       /*  The LCD is now in 4-bit mode so we can continue
+               using the 4-bit API */
+       _delay_us(50);
+}
+
+void HD44780_Initialise(void)
+{
+       PORTD &= ~ALL_BITS;
+       DDRD  |=  ALL_BITS;
+       HD44780_PowerUp4Bit();
+}
+
+void HD44780_WriteCommand(const uint8_t c)
+{
+       PORTD &= ~RS;
+       HD44780_WriteByte(c);
+       _delay_us(50);
+}
+
+void HD44780_WriteData(const uint8_t c)
+{
+       PORTD |=  RS;
+       HD44780_WriteByte(c);
+       PORTD &= ~RS;
+       _delay_us(50);
+}