mirror of
https://github.com/qmk/qmk_firmware.git
synced 2024-12-23 01:49:54 +00:00
128 lines
3.2 KiB
C
128 lines
3.2 KiB
C
|
/*
|
|||
|
|
LUFA Library
|
|||
|
|
Copyright (C) Dean Camera, 2017.
|
|||
|
|
|
|||
|
|
dean [at] fourwalledcubicle [dot] com
|
|||
|
|
www.lufa-lib.org
|
|||
|
|
*/
|
|||
|
|
|
|||
|
|
/*
|
|||
|
|
Copyright 2017 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 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
|
|||
|
|
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 <20>s */
|
|||
|
|
_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_Initialize(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);
|
|||
|
|
}
|