221 lines
6.4 KiB
C
221 lines
6.4 KiB
C
/*
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Copyright 2022
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <stdint.h>
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#include <stdbool.h>
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/**
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* \defgroup hd44780
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*
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* HD44780 Character LCD Driver
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* \{
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*/
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/*
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* HD44780 instructions
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* https://www.sparkfun.com/datasheets/LCD/HD44780.pdf
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* Table 6 (p24)
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*/
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// Clear display
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#define HD44780_CMD_CLEAR_DISPLAY 0x01
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// Return home
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#define HD44780_CMD_RETURN_HOME 0x02
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// Entry mode set
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#define HD44780_CMD_ENTRY_MODE 0x04
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#define HD44780_ENTRY_MODE_INC 0x02 // I/D
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#define HD44780_ENTRY_MODE_SHIFT 0x01 // S
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// Display on/off control
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#define HD44780_CMD_DISPLAY 0x08
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#define HD44780_DISPLAY_ON 0x04 // D
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#define HD44780_DISPLAY_CURSOR 0x02 // C
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#define HD44780_DISPLAY_BLINK 0x01 // B
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// Cursor or display shift
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#define HD44780_CMD_MOVE 0x10
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#define HD44780_MOVE_DISPLAY 0x08 // S/C
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#define HD44780_MOVE_RIGHT 0x04 // R/L
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// Function set
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#define HD44780_CMD_FUNCTION 0x20
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#define HD44780_FUNCTION_8_BIT 0x10 // DL
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#define HD44780_FUNCTION_2_LINES 0x08 // N
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#define HD44780_FUNCTION_5X10_DOTS 0x04 // F
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// Set CGRAM address
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#define HD44780_CMD_SET_CGRAM_ADDRESS 0x40
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// Set DDRAM address
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#define HD44780_CMD_SET_DDRAM_ADDRESS 0x80
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// Bitmask for busy flag when reading
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#define HD44780_BUSY_FLAG 0x80
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/**
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* \brief Write a byte to the display.
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*
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* \param data The byte to send to the display.
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* \param isData Whether the byte is an instruction or character data.
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*/
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void hd44780_write(uint8_t data, bool isData);
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/**
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* \brief Read a byte from the display.
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*
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* \param isData Whether to read the current cursor position, or the character at the cursor.
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*
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* \return 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.
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*/
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uint8_t hd44780_read(bool isData);
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/**
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* \brief Indicates whether the display is currently processing, and cannot accept instructions.
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*
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* \return `true` if the display is busy.
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*/
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bool hd44780_busy(void);
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/**
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* \brief Send a command to the display. Refer to the datasheet for the valid commands.
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*
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* This function waits for the display to clear the busy flag before sending the command.
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*
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* \param command The command to send.
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*/
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void hd44780_command(uint8_t command);
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/**
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* \brief Send a byte of data to the display.
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*
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* This function waits for the display to clear the busy flag before sending the data.
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*
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* \param data The byte of data to send.
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*/
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void hd44780_data(uint8_t data);
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/**
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* \brief Clear the display.
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*
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* This function is called on init.
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*/
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void hd44780_clear(void);
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/**
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* \brief Move the cursor to the home position.
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*
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* This function is called on init.
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*/
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void hd44780_home(void);
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/**
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* \brief Turn the display on, and/or set the cursor position.
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*
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* This function is called on init.
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*
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* \param cursor Whether to show the cursor.
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* \param blink Whether to blink the cursor, if shown.
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*/
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void hd44780_on(bool cursor, bool blink);
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/**
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* \brief Turn the display off.
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*/
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void hd44780_off(void);
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/**
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* \brief Set the CGRAM address.
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*
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* This function is used when defining custom characters.
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*
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* \param address The CGRAM address to move to, from `0x00` to `0x3F`.
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*/
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void hd44780_set_cgram_address(uint8_t address);
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/**
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* \brief Set the DDRAM address.
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*
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* This function is used when printing characters to the display, and setting the cursor.
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*
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* \param address The DDRAM address to move to, from `0x00` to `0x7F`.
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*/
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void hd44780_set_ddram_address(uint8_t address);
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/**
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* \brief Initialize the display.
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*
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* This function should be called only once, before any of the other functions can be called.
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*
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* \param cursor Whether to show the cursor.
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* \param blink Whether to blink the cursor, if shown.
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*/
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void hd44780_init(bool cursor, bool blink);
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/**
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* \brief Move the cursor to the specified position on the display.
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*
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* \param col The column number to move to, from 0 to 15 on 16x2 displays.
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* \param line The line number to move to, either 0 or 1 on 16x2 displays.
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*/
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void hd44780_set_cursor(uint8_t col, uint8_t line);
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/**
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* \brief Define a custom character.
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*
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* \param index The index of the custom character to define, from 0 to 7.
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* \param 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.
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*/
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void hd44780_define_char(uint8_t index, uint8_t *data);
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/**
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* \brief Print a character to the display. The newline character will move the cursor to the start of the next line.
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*
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* The exact character shown may depend on the ROM code of your particular display - refer to the datasheet for the full character set.
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*
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* \param c The character to print.
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*/
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void hd44780_putc(char c);
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/**
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* \brief Print a string of characters to the display.
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*
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* \param s The string to print.
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*/
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void hd44780_puts(const char *s);
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#if defined(__AVR__) || defined(__DOXYGEN__)
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/**
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* \brief Define a custom character from PROGMEM.
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*
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* On ARM devices, this function is simply an alias of hd44780_define_char().
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*
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* \param index The index of the custom character to define, from 0 to 7.
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* \param 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.
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*/
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void hd44780_define_char_P(uint8_t index, const uint8_t *data);
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/**
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* \brief Print a string of characters from PROGMEM to the display.
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*
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* On ARM devices, this function is simply an alias of hd44780_puts().
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*
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* \param s The PROGMEM string to print.
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*/
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void hd44780_puts_P(const char *s);
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#else
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# define hd44780_define_char_P(index, data) hd44780_define_char(index, data)
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# define hd44780_puts_P(s) hd44780_puts(s)
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#endif
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/** \} */
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