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-rw-r--r--Projects/SerialToLCD/Lib/HD44780.c127
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diff --git a/Projects/SerialToLCD/Lib/HD44780.c b/Projects/SerialToLCD/Lib/HD44780.c
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+/*
+ 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);
+}