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diff --git a/docs/feature_hd44780.md b/docs/feature_hd44780.md index dc476c734f..4ade640baa 100644 --- a/docs/feature_hd44780.md +++ b/docs/feature_hd44780.md @@ -1,57 +1,298 @@ -# HD44780 LCD Displays - -This is an integration of Peter Fleury's LCD library. This page will explain the basics. [For in depth documentation visit his page.](http://www.peterfleury.epizy.com/doxygen/avr-gcc-libraries/group__pfleury__lcd.html) - -You can enable support for HD44780 Displays by setting the `HD44780_ENABLE` flag in your keyboards `rules.mk` to yes. - -## Configuration - -You will need to configure the pins used by your display, and its number of lines and columns in your keyboard's `config.h`. - - -Uncomment the section labled HD44780 and change the parameters as needed. -```` -/* - * HD44780 LCD Display Configuration - */ - -#define LCD_LINES 2 //< number of visible lines of the display -#define LCD_DISP_LENGTH 16 //< visibles characters per line of the display -#define LCD_IO_MODE 1 //< 0: memory mapped mode, 1: IO port mode -#if LCD_IO_MODE -#define LCD_PORT PORTB //< port for the LCD lines -#define LCD_DATA0_PORT LCD_PORT //< port for 4bit data bit 0 -#define LCD_DATA1_PORT LCD_PORT //< port for 4bit data bit 1 -#define LCD_DATA2_PORT LCD_PORT //< port for 4bit data bit 2 -#define LCD_DATA3_PORT LCD_PORT //< port for 4bit data bit 3 -#define LCD_DATA0_PIN 4 //< pin for 4bit data bit 0 -#define LCD_DATA1_PIN 5 //< pin for 4bit data bit 1 -#define LCD_DATA2_PIN 6 //< pin for 4bit data bit 2 -#define LCD_DATA3_PIN 7 //< pin for 4bit data bit 3 -#define LCD_RS_PORT LCD_PORT //< port for RS line -#define LCD_RS_PIN 3 //< pin for RS line -#define LCD_RW_PORT LCD_PORT //< port for RW line -#define LCD_RW_PIN 2 //< pin for RW line -#define LCD_E_PORT LCD_PORT //< port for Enable line -#define LCD_E_PIN 1 //< pin for Enable line -#endif -```` - -Should you need to configure other properties you can copy them from `quantum/hd44780.h` and set them in your `config.h` +# HD44780 LCD Driver + +## Supported Hardware + +LCD modules using [HD44780U](https://www.sparkfun.com/datasheets/LCD/HD44780.pdf) IC or equivalent, communicating in 4-bit mode. + +|Module|Size |Notes | +|------|--------------|---------------------------------| +|1602A |16x2, 5x8 dots| | +|2004A |20x4, 5x8 dots|Untested, not currently supported| + +To run these modules at 3.3V, an additional MAX660 voltage converter IC must be soldered on, along with two 10µF capacitors. See [this page](https://www.codrey.com/electronic-circuits/hack-your-16x2-lcd/) for more details. ## Usage -To initialize your display, call `lcd_init()` with one of these parameters: -```` -LCD_DISP_OFF : display off -LCD_DISP_ON : display on, cursor off -LCD_DISP_ON_CURSOR : display on, cursor on -LCD_DISP_ON_CURSOR_BLINK : display on, cursor on flashing -```` -This is best done in your keyboards `matrix_init_kb` or your keymaps `matrix_init_user`. -It is advised to clear the display before use. -To do so call `lcd_clrscr()`. +Add the following to your `rules.mk`: + +```make +HD44780_ENABLE = yes +``` + +## Basic Configuration + +Add the following to your `config.h`: + +|Define |Default |Description | +|-----------------------|--------------|-----------------------------------------------------------------------------------------------------| +|`HD44780_DATA_PINS` |*Not defined* |(Required) An array of four GPIO pins connected to the display's D4-D7 pins, eg. `{ B1, B3, B2, B6 }`| +|`HD44780_RS_PIN` |*Not defined* |(Required) The GPIO connected to the display's RS pin | +|`HD44780_RW_PIN` |*Not defined* |(Required) The GPIO connected to the display's RW pin | +|`HD44780_E_PIN` |*Not defined* |(Required) The GPIO connected to the display's E pin | +|`HD44780_DISPLAY_COLS` |`16` |The number of visible characters on a single line of the display | +|`HD44780_DISPLAY_LINES`|`2` |The number of visible lines on the display | +|`HD44780_WRAP_LINES` |*Not defined* |If defined, input characters will wrap to the next line | + +## Examples + +### Hello World + +Add the following to your `keymap.c`: + +```c +void keyboard_post_init_user(void) { + hd44780_init(true, true); // Show blinking cursor + hd44780_puts_P(PSTR("Hello, world!\n")); +} +``` + +### Custom Character Definition + +Up to eight custom characters can be defined. This data is stored in the Character Generator RAM (CGRAM), and is not persistent across power cycles. + +This example defines the QMK Psi as the first custom character. The first 16 positions in the character set are reserved for the eight custom characters duplicated. + +``` +Byte | 16 8 4 2 1 + 1 | x x x ■ □ ■ □ ■ + 2 | x x x ■ □ ■ □ ■ + 3 | x x x ■ □ ■ □ ■ + 4 | x x x □ ■ ■ ■ □ + 5 | x x x □ □ ■ □ □ + 6 | x x x □ □ ■ □ □ + 7 | x x x □ □ ■ □ □ + 8 | x x x □ □ □ □ □ +``` + +```c +const uint8_t PROGMEM psi[8] = { 0x15, 0x15, 0x15, 0x0E, 0x04, 0x04, 0x04, 0x00 }; + +void keyboard_post_init_user(void) { + hd44780_init(false, false); + hd44780_define_char_P(0, psi); + // Cursor is incremented while defining characters so must be reset + hd44780_home(); + // 0x08 to avoid null terminator + hd44780_puts_P(PSTR("\x08 QMK Firmware")); +} +``` + +## API + +### `void hd44780_init(bool cursor, bool blink)` + +Initialize the display. + +This function should be called only once, before any of the other functions can be called. + +#### Arguments + + - `bool cursor` + Whether to show the cursor. + - `bool blink` + Whether to blink the cursor, if shown. + +--- + +### `void hd44780_clear(void)` + +Clear the display. + +This function is called on init. + +--- + +### `void hd44780_home(void)` + +Move the cursor to the home position. + +This function is called on init. + +--- + +### `void hd44780_on(bool cursor, bool blink)` + +Turn the display on, and/or set the cursor properties. + +This function is called on init. + +#### Arguments + + - `bool cursor` + Whether to show the cursor. + - `bool blink` + Whether to blink the cursor, if shown. + +--- + +### `void hd44780_off(void)` + +Turn the display off. + +--- + +### `void hd44780_set_cursor(uint8_t col, uint8_t line)` + +Move the cursor to the specified position on the display. + +#### Arguments + + - `uint8_t col` + The column number to move to, from 0 to 15 on 16x2 displays. + - `bool line` + The line number to move to, either 0 or 1 on 16x2 displays. + +--- + +### `void hd44780_putc(char c)` + +Print a character to the display. The newline character `\n` will move the cursor to the start of the next line. + +The exact character shown may depend on the ROM code of your particular display - refer to the datasheet for the full character set. + +#### Arguments + + - `char c` + The character to print. + +--- + +### `void hd44780_puts(const char *s)` + +Print a string of characters to the display. + +#### Arguments + + - `const char *s` + The string to print. + +--- + +### `void hd44780_puts_P(const char *s)` + +Print a string of characters from PROGMEM to the display. + +On ARM devices, this function is simply an alias of `hd44780_puts()`. + +#### Arguments + + - `const char *s` + The PROGMEM string to print (ie. `PSTR("Hello")`). + +--- + +### `void hd44780_define_char(uint8_t index, uint8_t *data)` + +Define a custom character. + +#### Arguments + + - `uint8_t index` + The index of the custom character to define, from 0 to 7. + - `uint8_t *data` + An array of 8 bytes containing the 5-bit row data of the character, where the first byte is the topmost row, and the least significant bit of each byte is the rightmost column. + +--- + +### `void hd44780_define_char_P(uint8_t index, const uint8_t *data)` + +Define a custom character from PROGMEM. + +On ARM devices, this function is simply an alias of `hd44780_define_char()`. + +#### Arguments + + - `uint8_t index` + The index of the custom character to define, from 0 to 7. + - `const uint8_t *data` + A PROGMEM array of 8 bytes containing the 5-bit row data of the character, where the first byte is the topmost row, and the least significant bit of each byte is the rightmost column. + +--- + +### `bool hd44780_busy(void)` + +Indicates whether the display is currently processing, and cannot accept instructions. + +#### Return Value + +`true` if the display is busy. + +--- + +### `void hd44780_write(uint8_t data, bool isData)` + +Write a byte to the display. + +#### Arguments + + - `uint8_t data` + The byte to send to the display. + - `bool isData` + Whether the byte is an instruction or character data. + +--- + +### `uint8_t hd44780_read(bool isData)` + +Read a byte from the display. + +#### Arguments + + - `bool isData` + Whether to read the current cursor position, or the character at the cursor. + +#### Return Value + +If `isData` is `true`, the returned byte will be the character at the current DDRAM address. Otherwise, it will be the current DDRAM address and the busy flag. + +--- + +### `void hd44780_command(uint8_t command)` + +Send a command to the display. Refer to the datasheet and `hd44780.h` for the valid commands and defines. + +This function waits for the display to clear the busy flag before sending the command. + +#### Arguments + + - `uint8_t command` + The command to send. + +--- + +### `void hd44780_data(uint8_t data)` + +Send a byte of data to the display. + +This function waits for the display to clear the busy flag before sending the data. + +#### Arguments + + - `uint8_t data` + The byte of data to send. + +--- + +### `void hd44780_set_cgram_address(uint8_t address)` + +Set the CGRAM address. + +This function is used when defining custom characters. + +#### Arguments + + - `uint8_t address` + The CGRAM address to move to, from `0x00` to `0x3F`. + +--- + +### `void hd44780_set_ddram_address(uint8_t address)` + +Set the DDRAM address. + +This function is used when printing characters to the display, and setting the cursor. -To now print something to your Display you first call `lcd_gotoxy(column, line)`. To go to the start of the first line you would call `lcd_gotoxy(0, 0)` and then print a string with `lcd_puts("example string")`. +#### Arguments -There are more methods available to control the display. [For in depth documentation please visit the linked page.](http://www.peterfleury.epizy.com/doxygen/avr-gcc-libraries/group__pfleury__lcd.html) + - `uint8_t address` + The DDRAM address to move to, from `0x00` to `0x7F`. |