/*
LUFA Library
- Copyright (C) Dean Camera, 2012.
+ Copyright (C) Dean Camera, 2015.
dean [at] fourwalledcubicle [dot] com
www.lufa-lib.org
*/
/*
- Copyright 2012 Dean Camera (dean [at] fourwalledcubicle [dot] com)
+ Copyright 2015 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
advertising or publicity pertaining to distribution of the
software without specific, written prior permission.
- The author disclaim all warranties with regard to this
+ The author disclaims 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
static void HD44780_WriteNibble(const uint8_t nib)
{
- /* Read PORTD and clear the ENABLE and PD0..3 bits
+ /* 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
+
+ /* 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"
/* 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"
/* 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