j3d1/esp-open-rtos
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

Driver for HD44780 LCDs connected directly to GPIO / to I2C by PCF8574-like GPIO expanders

Browse source
This commit is contained in:
UncleRus 2016-10-22 07:19:10 +05:00
parent 2994a566a6
commit 4fdbaa2108
9 changed files with 457 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

189
extras/hd44780/hd44780.c Normal file
View file

@ -0,0 +1,189 @@
#include "hd44780.h"
#if (HD44780_I2C)
#include <pcf8574/pcf8574.h>
#else
#include <esp/gpio.h>
#endif
#include <espressif/esp_common.h>
#define MS 1000
#define DELAY_CMD_LONG (3 * MS) // >1.53ms according to datasheet
#define DELAY_CMD_SHORT (60) // >39us according to datasheet
#define DELAY_TOGGLE (10)
#define DELAY_INIT (5 * MS)
#define CMD_CLEAR 0x01
#define CMD_RETURN_HOME 0x02
#define CMD_ENTRY_MODE 0x04
#define CMD_DISPLAY_CTRL 0x08
#define CMD_SHIFT 0x10
#define CMD_FUNC_SET 0x20
#define CMD_CGRAM_ADDR 0x40
#define CMD_DDRAM_ADDR 0x80
// CMD_ENTRY_MODE
#define ARG_EM_INCREMENT (1 << 1)
#define ARG_EM_SHIFT (1)
// CMD_DISPLAY_CTRL
#define ARG_DC_DISPLAY_ON (1 << 2)
#define ARG_DC_CURSOR_ON (1 << 1)
#define ARG_DC_CURSOR_BLINK (1)
// CMD_FUNC_SET
#define ARG_FS_8_BIT (1 << 4)
#define ARG_FS_2_LINES (1 << 3)
#define ARG_FS_FONT_5X10 (1 << 2)
#if (HD44780_I2C)
#define init_delay() do { sdk_os_delay_us(DELAY_INIT); } while (0)
#define short_delay()
#define long_delay() do { sdk_os_delay_us(DELAY_CMD_LONG); } while (0)
#else
#define init_delay() do { sdk_os_delay_us(DELAY_INIT); } while (0)
#define short_delay() do { sdk_os_delay_us(DELAY_CMD_SHORT); } while (0)
#define long_delay() do { sdk_os_delay_us(DELAY_CMD_LONG); } while (0)
#define toggle_delay() do { sdk_os_delay_us(DELAY_TOGGLE); } while (0)
#endif
static const uint8_t line_addr[] = { 0x00, 0x40, 0x14, 0x54 };
static void write_nibble(const hd44780_t *lcd, uint8_t b, bool rs)
{
#if (HD44780_I2C)
uint8_t data = (((b >> 3) & 1) << lcd->pins.d7)
| (((b >> 2) & 1) << lcd->pins.d6)
| (((b >> 1) & 1) << lcd->pins.d5)
| ((b & 1) << lcd->pins.d4)
| (rs ? 1 << lcd->pins.rs : 0)
| (lcd->backlight ? 1 << lcd->pins.bl : 0);
pcf8574_port_write(lcd->addr, data | (1 << lcd->pins.e));
pcf8574_port_write(lcd->addr, data);
#else
gpio_write(lcd->pins.d7, (b >> 3) & 1);
gpio_write(lcd->pins.d6, (b >> 2) & 1);
gpio_write(lcd->pins.d5, (b >> 1) & 1);
gpio_write(lcd->pins.d4, b & 1);
gpio_write(lcd->pins.rs, rs);
gpio_write(lcd->pins.e, true);
toggle_delay();
gpio_write(lcd->pins.e, false);
#endif
}
static void write_byte(const hd44780_t *lcd, uint8_t b, bool rs)
{
write_nibble(lcd, b >> 4, rs);
write_nibble(lcd, b, rs);
}
void hd44780_init(const hd44780_t *lcd)
{
#if (!HD44780_I2C)
gpio_enable(lcd->pins.rs, GPIO_OUTPUT);
gpio_enable(lcd->pins.e, GPIO_OUTPUT);
gpio_enable(lcd->pins.d4, GPIO_OUTPUT);
gpio_enable(lcd->pins.d5, GPIO_OUTPUT);
gpio_enable(lcd->pins.d6, GPIO_OUTPUT);
gpio_enable(lcd->pins.d7, GPIO_OUTPUT);
if (lcd->pins.bl != HD44780_NOT_USED)
gpio_enable(lcd->pins.bl, GPIO_OUTPUT);
#endif
// switch to 4 bit mode
for (uint8_t i = 0; i < 3; i ++)
{
write_nibble(lcd, (CMD_FUNC_SET | ARG_FS_8_BIT) >> 4, false);
init_delay();
}
write_nibble(lcd, CMD_FUNC_SET >> 4, false);
// Specify the number of display lines and character font
write_byte(lcd,
CMD_FUNC_SET
| (lcd->lines > 1 ? ARG_FS_2_LINES : 0)
| (lcd->font == HD44780_FONT_5X10 ? ARG_FS_FONT_5X10 : 0),
false);
short_delay();
// Display off
hd44780_control(lcd, false, false, false);
// Clear
hd44780_clear(lcd);
// Entry mode set
write_byte(lcd, CMD_ENTRY_MODE | ARG_EM_INCREMENT, false);
short_delay();
// Display on
hd44780_control(lcd, true, false, false);
}
void hd44780_control(const hd44780_t *lcd, bool on, bool cursor, bool cursor_blink)
{
write_byte(lcd,
CMD_DISPLAY_CTRL
| (on ? ARG_DC_DISPLAY_ON : 0)
| (cursor ? ARG_DC_CURSOR_ON : 0)
| (cursor_blink ? ARG_DC_CURSOR_BLINK : 0),
false);
short_delay();
}
void hd44780_clear(const hd44780_t *lcd)
{
write_byte(lcd, CMD_CLEAR, false);
long_delay();
}
void hd44780_gotoxy(const hd44780_t *lcd, uint8_t col, uint8_t line)
{
if (line >= lcd->lines) line = lcd->lines - 1;
uint8_t addr = line < sizeof(line_addr) ? line_addr[line] : 0;
write_byte(lcd, CMD_DDRAM_ADDR + addr + col, false);
short_delay();
}
void hd44780_putc(const hd44780_t *lcd, char c)
{
write_byte(lcd, c, true);
short_delay();
}
void hd44780_puts(const hd44780_t *lcd, const char *s)
{
while (*s)
{
hd44780_putc(lcd, *s);
s++;
}
}
void hd44780_set_backlight(hd44780_t *lcd, bool on)
{
if (lcd->pins.bl == HD44780_NOT_USED)
return;
#if (HD44780_I2C)
pcf8574_gpio_write(lcd->addr, lcd->pins.bl, on);
#else
gpio_write(lcd->pins.bl, on);
#endif
lcd->backlight = on;
}
void hd44780_upload_character(const hd44780_t *lcd, uint8_t num, const uint8_t *data)
{
if (num > 7) return;
uint8_t bytes = lcd->font == HD44780_FONT_5X8 ? 8 : 10;
write_byte(lcd, CMD_CGRAM_ADDR + num * bytes, false);
short_delay();
for (uint8_t i = 0; i < bytes; i ++)
{
write_byte(lcd, data[i], true);
short_delay();
}
hd44780_gotoxy(lcd, 0, 0);
}