/*
LUFA Library
- Copyright (C) Dean Camera, 2013.
+ Copyright (C) Dean Camera, 2014.
dean [at] fourwalledcubicle [dot] com
www.lufa-lib.org
*/
/*
- Copyright 2013 Dean Camera (dean [at] fourwalledcubicle [dot] com)
+ Copyright 2014 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
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