Some old AVR projects
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#pragma once
#include <stdbool.h>
#include <stdint.h>
#include <avr/io.h>
#include <avr/pgmspace.h>
#include <util/delay.h>
#include "calc.h"
#include "pins.h"
#include "nsdelay.h"
/*
HD44780 LCD display driver - 4-bit mode
Required macros - pin settings (eg. B,3 or D,0)
LCD_PIN_RS
LCD_PIN_RW
LCD_PIN_E
LCD_PIN_D7
LCD_PIN_D6
LCD_PIN_D5
LCD_PIN_D4
Define those before including the header file.
*/
// Commands for user
// Clear screen (reset)
#define LCD_CLEAR 0b00000001
// Move cursor to (0,0), unshift...
#define LCD_HOME 0b00000010
// Set mode: Increment + NoShift
#define LCD_MODE_INC 0b00000110
// Set mode: Increment + Shift
#define LCD_MODE_INC_SHIFT 0b00000111
// Set mode: Decrement + NoShift
#define LCD_MODE_DEC 0b00000100
// Set mode: Decrement + Shift
#define LCD_MODE_DEC_SHIFT 0b00000101
// Disable display (data remains untouched)
#define LCD_DISABLE 0b00001000
// Disable cursor
#define LCD_CURSOR_NONE 0b00001100
// Set cursor to still underscore
#define LCD_CURSOR_BAR 0b00001110
// Set cursor to blinking block
#define LCD_CURSOR_BLINK 0b00001101
// Set cursor to both of the above at once
#define LCD_CURSOR_BOTH (LCD_CURSOR_BAR | LCD_CURSOR_BLINK)
// Move cursor
#define LCD_MOVE_LEFT 0b00010000
#define LCD_MOVE_RIGHT 0b00010100
// Shift display
#define LCD_SHIFT_LEFT 0b00011000
#define LCD_SHIFT_RIGHT 0b00011100
// Set iface to 5x7 font, 1-line
#define LCD_IFACE_4BIT_1LINE 0b00100000
#define LCD_IFACE_8BIT_1LINE 0b00110000
// Set iface to 5x7 font, 2-line
#define LCD_IFACE_4BIT_2LINE 0b00101000
#define LCD_IFACE_8BIT_2LINE 0b00111000
// Start address of rows
const uint8_t LCD_ROW_ADDR[] = {0x00, 0x40, 0x14, 0x54};
// prototypes
// --- PUBLIC API ---
/** Init the display */
void lcd_init();
/** Write a command */
void lcd_write_command(const uint8_t bb);
/** Write data byte */
void lcd_write_data(const uint8_t bb);
/** Read busy flag & address */
uint8_t lcd_read_bf_addr();
/** Read byte from ram */
uint8_t lcd_read_ram();
/** Show string */
void lcd_str(char* str);
/** Show string at X, Y */
#define lcd_str_xy(x, y, str_p) do { lcd_xy((x), (y)); lcd_str((str_p)); } while(0)
/** Show char */
void lcd_char(const char c);
/** Show char at X, Y */
#define lcd_char_xy(x, y, c) do { lcd_xy((x), (y)); lcd_char((c)); } while(0)
/** Move cursor to X, Y */
void lcd_xy(const uint8_t x, const uint8_t y);
/** Set address in CGRAM */
void lcd_set_addr_cgram(const uint8_t acg);
/** Set address in DDRAM */
void lcd_set_addr(const uint8_t add);
/** Go home */
void lcd_home();
/** Clear the screen */
void lcd_clear();
/** Set cursor */
#define CURSOR_NONE 0b00
#define CURSOR_BAR 0b10
#define CURSOR_BLINK 0b01
#define CURSOR_BOTH 0b11
void lcd_cursor(uint8_t type);
/** Disable / enable, preserving cursor */
void lcd_disable();
void lcd_enable();
/** Define a custom glyph */
void lcd_define_glyph(const uint8_t index, const uint8_t* array);
// Internals
void _lcd_mode_r();
void _lcd_mode_w();
void _lcd_clk();
void _lcd_wait_bf();
void _lcd_write_byte(uint8_t bb);
uint8_t _lcd_read_byte();
// Write utilities
#define _lcd_write_low(bb) _lcd_write_nibble((bb) & 0x0F)
#define _lcd_write_high(bb) _lcd_write_nibble(((bb) & 0xF0) >> 4)
#define _lcd_write_nibble(nib) do { \
write_pin(LCD_PIN_D7, get_bit((nib), 3)); \
write_pin(LCD_PIN_D6, get_bit((nib), 2)); \
write_pin(LCD_PIN_D5, get_bit((nib), 1)); \
write_pin(LCD_PIN_D4, get_bit((nib), 0)); \
} while(0)
// 0 W, 1 R
bool _lcd_mode;
/** Initialize the display */
void lcd_init()
{
// configure pins as output
as_output(LCD_PIN_E);
as_output(LCD_PIN_RW);
as_output(LCD_PIN_RS);
_lcd_mode = 1; // force data pins to output
_lcd_mode_w();
// Magic sequence to enter 4-bit mode
_delay_ms(16);
_lcd_write_nibble(0b0011);
_lcd_clk();
_delay_ms(5);
_lcd_clk();
_delay_ms(5);
_lcd_clk();
_delay_ms(5);
_lcd_write_nibble(0b0010);
_lcd_clk();
_delay_us(100);
// Configure the display
lcd_write_command(LCD_IFACE_4BIT_2LINE);
lcd_write_command(LCD_DISABLE);
lcd_write_command(LCD_CLEAR);
lcd_write_command(LCD_MODE_INC);
lcd_enable();
}
/** Send a pulse on the ENABLE line */
void _lcd_clk()
{
pin_up(LCD_PIN_E);
delay_ns(420);
pin_down(LCD_PIN_E);
}
/** Enter READ mode */
void _lcd_mode_r()
{
if (_lcd_mode == 1) return; // already in R mode
pin_up(LCD_PIN_RW);
as_input_pu(LCD_PIN_D7);
as_input_pu(LCD_PIN_D6);
as_input_pu(LCD_PIN_D5);
as_input_pu(LCD_PIN_D4);
_lcd_mode = 1;
}
/** Enter WRITE mode */
void _lcd_mode_w()
{
if (_lcd_mode == 0) return; // already in W mode
pin_down(LCD_PIN_RW);
as_output(LCD_PIN_D7);
as_output(LCD_PIN_D6);
as_output(LCD_PIN_D5);
as_output(LCD_PIN_D4);
_lcd_mode = 0;
}
/** Read a byte */
uint8_t _lcd_read_byte()
{
_lcd_mode_r();
uint8_t res = 0;
_lcd_clk();
res = (read_pin(LCD_PIN_D7) << 7) | (read_pin(LCD_PIN_D6) << 6) | (read_pin(LCD_PIN_D5) << 5) | (read_pin(LCD_PIN_D4) << 4);
_lcd_clk();
res |= (read_pin(LCD_PIN_D7) << 3) | (read_pin(LCD_PIN_D6) << 2) | (read_pin(LCD_PIN_D5) << 1) | (read_pin(LCD_PIN_D4) << 0);
return res;
}
/** Write an instruction byte */
void lcd_write_command(uint8_t bb)
{
_lcd_wait_bf();
pin_down(LCD_PIN_RS); // select instruction register
_lcd_write_byte(bb); // send instruction byte
}
/** Write a data byte */
void lcd_write_data(uint8_t bb)
{
_lcd_wait_bf();
pin_up(LCD_PIN_RS); // select data register
_lcd_write_byte(bb); // send data byte
}
/** Read BF & Address */
uint8_t lcd_read_bf_addr()
{
pin_down(LCD_PIN_RS);
return _lcd_read_byte();
}
/** Read CGRAM or DDRAM */
uint8_t lcd_read_ram()
{
pin_up(LCD_PIN_RS);
return _lcd_read_byte();
}
/** Write a byte using the 8-bit interface */
void _lcd_write_byte(uint8_t bb)
{
_lcd_mode_w(); // enter W mode
_lcd_write_high(bb);
_lcd_clk();
_lcd_write_low(bb);
_lcd_clk();
}
/** Wait until the device is ready */
void _lcd_wait_bf()
{
uint8_t d = 0;
while(d++ < 120 && lcd_read_bf_addr() & _BV(7))
_delay_us(1);
}
/** Send a string to LCD */
void lcd_str(char* str_p)
{
while (*str_p)
lcd_char(*str_p++);
}
/** Sedn a char to LCD */
void lcd_char(const char c)
{
lcd_write_data(c);
}
/** Set cursor position */
void lcd_xy(const uint8_t x, const uint8_t y)
{
lcd_set_addr(LCD_ROW_ADDR[y] + (x));
}
uint8_t _lcd_old_cursor = CURSOR_NONE;
bool _lcd_enabled = false;
/** Set LCD cursor. If not enabled, only remember it. */
void lcd_cursor(uint8_t type)
{
_lcd_old_cursor = (type & CURSOR_BOTH);
if (_lcd_enabled) lcd_write_command(LCD_CURSOR_NONE | _lcd_old_cursor);
}
/** Display display (preserving cursor) */
void lcd_disable()
{
lcd_write_command(LCD_DISABLE);
_lcd_enabled = false;
}
/** Enable display (restoring cursor) */
void lcd_enable()
{
_lcd_enabled = true;
lcd_cursor(_lcd_old_cursor);
}
/** Go home */
void lcd_home()
{
lcd_write_command(LCD_HOME);
}
/** Clear the screen */
void lcd_clear()
{
lcd_write_command(LCD_CLEAR);
}
/** Define a glyph */
void lcd_define_glyph(const uint8_t index, const uint8_t* array)
{
lcd_set_addr_cgram(index * 8);
for (uint8_t i = 0; i < 8; ++i) {
lcd_write_data(array[i]);
}
}
/** Define a glyph */
void lcd_define_glyph_pgm(const uint8_t index, const uint8_t* array)
{
lcd_set_addr_cgram(index * 8);
for (uint8_t i = 0; i < 8; ++i) {
lcd_write_data(pgm_read_byte(&array[i]));
}
}
/** Set address in CGRAM */
void lcd_set_addr_cgram(const uint8_t acg)
{
lcd_write_command(0b01000000 | ((acg) & 0b00111111));
}
/** Set address in DDRAM */
void lcd_set_addr(const uint8_t add)
{
lcd_write_command(0b10000000 | ((add) & 0b01111111));
}