316 lines
11 KiB
C++
316 lines
11 KiB
C++
static const int dummyvar = 0; // dummy declaration for older broken IDEs!!!!
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// vi:ts=4
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// ----------------------------------------------------------------------------
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// LCDCustomChars - simple demonstration of lcd custom characters
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// Created by Bill Perry 2016-10-06
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// bperrybap@opensource.billsworld.billandterrie.com
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//
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// This example code is unlicensed and is released into the public domain
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// ----------------------------------------------------------------------------
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//
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// This sketch is for LCDs with PCF8574 or MCP23008 chip based backpacks
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// WARNING:
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// Use caution when using 3v only processors like arm and ESP8266 processors
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// when interfacing with 5v modules as not doing proper level shifting or
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// incorrectly hooking things up can damage the processor.
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//
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// Sketch demonstrates how to assign custom characters to the eight hd44780
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// custom character codepoints and how to display on the LCD using
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// write() and print()
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//
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// You can create your own custom characters.
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// Here are a couple of web pages that have a tool that will generate the data
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// values needed for custom character.
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// https://kakedev.github.io/GlyphGenerator/
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// http://www.quinapalus.com/hd44780udg.html
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// https://omerk.github.io/lcdchargen
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//
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#include <Wire.h>
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#include <hd44780.h> // include hd44780 library header file
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#include <hd44780ioClass/hd44780_I2Cexp.h> // i/o expander/backpack class
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hd44780_I2Cexp lcd; // auto detect backpack and pin mappings
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// LCD geometry
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const int LCD_COLS = 16;
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const int LCD_ROWS = 2;
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const int LongDelay = 5000;
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const int ShortDelay = 800;
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int customcharRow = 1; // default to printing custom chars on row 1
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// Below are some custom characters for demonstration
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// You can ensure that the data for these custom characters is only
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// in flash and not in RAM by using the const qualifier.
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// However....
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// If using the AVR part, the AVR proprietary PROGMEM directive must be used.
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// PROGMEM is only required on AVR parts since the AVR parts cannot directly
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// access const data stored in flash like all the other processors.
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// PROGMEM is an AVR specific proprietary kludge that tells the linker and
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// startup code to handle the data differently.
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// PROGMEM is only used by the AVR and not required by any other processor.
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//
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// Most non AVR cores provide AVR compatibilty by providing support (emulation)
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// for the AVR proprietary PROGMEM directive and corresponding access functions,
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// but some do not.
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//
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// Because of this AVR const data and PROGMEM issue, there is no way to
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// guarantee code portability across all cores when using const data.
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//
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//
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// the hd44780 library assumes that if a const qualifier is used on the AVR
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// processor that the data has been stored in flash using the PROGMEM directive.
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// There is no way for the hd44780 library to know or detect if PROGMEM has
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// been used.
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// So if the const qualifer is used but the PROGMEM directive is not used on
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// an AVR processor, the custom char will be garbage.
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//
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// Examples:
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// For all processors other than AVR:
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// const char bell[8] = {0x04,0x0e,0x0e,0x0e,0x1f,0x00,0x04,0x00};
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// const uint8_ bell[8] = {0x04,0x0e,0x0e,0x0e,0x1f,0x00,0x04,0x00};
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//
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// For AVR: (and non AVR cores that have AVR PROGMEM emulation)
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// const char bell[8] PROGMEM = {0x04,0x0e,0x0e,0x0e,0x1f,0x00,0x04,0x00};
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// const uint8_t bell[8] PROGMEM = {0x04,0x0e,0x0e,0x0e,0x1f,0x00,0x04,0x00};
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// OR
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// const PROGMEM char bell[8] = {0x04,0x0e,0x0e,0x0e,0x1f,0x00,0x04,0x00};
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// const PROGMEM uint8_t bell[8] = {0x04,0x0e,0x0e,0x0e,0x1f,0x00,0x04,0x00};
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// NOTE:
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// if PROGMEM is used on older AVR compilers it generates a warning.
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//
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uint8_t bell[8] = {0x04,0x0e,0x0e,0x0e,0x1f,0x00,0x04,0x00};
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uint8_t note[8] = {0x02,0x03,0x02,0x0e,0x1e,0x0c,0x00,0x00};
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uint8_t clockface[8] = {0x00,0x0e,0x15,0x17,0x11,0x0e,0x00,0x00};
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uint8_t heart[8] = {0x00,0x0a,0x1f,0x1f,0x0e,0x04,0x00,0x00};
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uint8_t duck[8] = {0x00,0x0c,0x1d,0x0f,0x0f,0x06,0x00,0x00};
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uint8_t check[8] = {0x00,0x01,0x03,0x16,0x1c,0x08,0x00,0x00};
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uint8_t cross[8] = {0x00,0x1b,0x0e,0x04,0x0e,0x1b,0x00,0x00};
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uint8_t smile[8] = {0x00,0x0a,0x0a,0x00,0x00,0x11,0x0e,0x00};
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uint8_t degreeSymbol[8]= {0x06,0x09,0x09,0x06,0x00,0x00,0x00,0x00};
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uint8_t degreeC[8] = {0x18,0x18,0x03,0x04,0x04,0x04,0x03,0x00};
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uint8_t degreeF[8] = {0x18,0x18,0x07,0x04,0x07,0x04,0x04,0x00};
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const PROGMEM uint8_t vsigbar[][8] = {
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{0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x00}, // 0 bars, same as <space>
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{0x00, 0x00,0x00,0x00,0x00,0x00,0x00,0x1F}, // 1 bars
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{0x00, 0x00,0x00,0x00,0x00,0x00,0x1F,0x1F}, // 2 bars
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{0x00, 0x00,0x00,0x00,0x00,0x1F,0x1F,0x1F}, // 3 bars
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{0x00, 0x00,0x00,0x00,0x1F,0x1F,0x1F,0x1F}, // 4 bars
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{0x00, 0x00,0x00,0x1F,0x1F,0x1F,0x1F,0x1F}, // 5 bars
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{0x00, 0x00,0x1F,0x1F,0x1F,0x1F,0x1F,0x1F}, // 6 bars
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{0x00, 0x1F,0x1F,0x1F,0x1F,0x1F,0x1F,0x1F}, // 7 bars
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{0x1F, 0x1F,0x1F,0x1F,0x1F,0x1F,0x1F,0x1F}, // 8 bars
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};
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void setup()
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{
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int status;
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// initialize LCD with number of columns and rows:
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// hd44780 returns a status from begin() that can be used
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// to determine if initalization failed.
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// the actual status codes are defined in <hd44780.h>
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// See the values RV_XXXX
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//
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// looking at the return status from begin() is optional
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// it is being done here to provide feedback should there be an issue
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//
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// note:
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// begin() will automatically turn on the backlight
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//
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status = lcd.begin(LCD_COLS, LCD_ROWS);
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if(status) // non zero status means it was unsuccesful
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{
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// begin() failed so blink error code using the onboard LED if possible
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hd44780::fatalError(status); // does not return
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}
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// initalization was successful, the backlight should be on now
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}
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void loop(void)
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{
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lcd.clear();
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lcd.print("Custom Chars");
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// create custom characters
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// int rval = createChar(charval, charmap[]);
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//
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// createChar() creates a custom character
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// for the character at the charval codepoint.
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// It returns zero if successful.
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//
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// to display the custom character, simply call write()
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// with the charval use in createChar()
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//
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// The display must be initialized *before* you attempt
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// to create custom characters.
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//
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// Note: On hd44780 displays there are 8 custom characters.
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// They are assigned to character codepoint values 0x00 to 0x07
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// The codepoints 0x08 to 0x0f are duplicates for 0x00 to 0x07
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// i.e. 0x08 is the same as 0x00, 0x09 same as 0x01, etc...
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// create 8 custom characters
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lcd.createChar(0, bell);
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lcd.createChar(1, note);
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lcd.createChar(2, clockface);
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lcd.createChar(3, heart);
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lcd.createChar(4, duck);
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lcd.createChar(5, check);
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lcd.createChar(6, cross);
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lcd.createChar(7, smile);
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// prepare to display the custom characters
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// on multi line displays the custom characters will be
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// displayed on the 2nd line
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// on single line displays, delay a bit to see the initial display,
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// then clear the display to display the custom characters on the top line
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if(LCD_ROWS < 2)
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{
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customcharRow = 0;
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delay(LongDelay);
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lcd.clear();
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}
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lcd.setCursor(0, customcharRow);
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// write() or print() can be used to display custom characters.
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//
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// To use write() pass the charval of the desired custom character.
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// lcd.write(charval);
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// NOTE:
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// The Print class has an issue that does not allow 0 (zero) to be used
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// on write() without casting it. The Arduino team refuses to fix this.
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// hd44780 has a work around in it to remove this issue so you can call
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// write() with a constant value of 0 without having to cast it.
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//
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// write() can also be used with literal characters that contain
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// an octal (base 8) escape seuence.
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// lcd.write('\###');
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//
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// To use print() pass in the charval of the desired custom character
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// as a character *not* an integer.
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// This requires using a literal character with an octal escape sequence.
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// lcd.print('\###');
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//
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// Since both write() & print() both accept octal escaped literal characters
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// it is the most compatible & portable way of sending custom characters
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// display all 8 custom characters.
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// write() with character codepoint values
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lcd.write(0); // casting to an uint8_t or byte not needed with hd44780
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lcd.write(1);
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// write() & print() with octal escaped literal characters
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lcd.write('\002'); // this is an octal escaped literal character
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lcd.write('\003'); // this is an octal escaped literal character
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lcd.print('\004'); // this is an octal escaped literal character
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lcd.print('\005'); // this is an octal escaped literal character
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// can also drop the leading zeros on small litereal values like these
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lcd.print('\06'); // this is an octal escaped literal character
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lcd.print('\7'); // this is an octal escaped literal character
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delay(LongDelay);
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// You can also insert custom character codepoints into C strings.
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// To do so, insert the character codepoint value as an octal constant.
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// However,
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// because zero indicates the end of string in C you cannot use zero.
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// Example:
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// lcd.print("charval #1: \001"); // prints custom character at codepoint 1
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lcd.setCursor(0,customcharRow);
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lcd.print("code1: \001");
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delay(ShortDelay);
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lcd.setCursor(0,customcharRow);
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lcd.print("code2: \002");
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delay(ShortDelay);
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lcd.setCursor(0,customcharRow);
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lcd.print("code3: \003");
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delay(ShortDelay);
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lcd.setCursor(0,customcharRow);
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lcd.print("code4: \004");
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delay(ShortDelay);
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lcd.setCursor(0,customcharRow);
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lcd.print("code5: \005");
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delay(ShortDelay);
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lcd.setCursor(0,customcharRow);
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lcd.print("code6: \006");
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delay(ShortDelay);
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lcd.setCursor(0,customcharRow);
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lcd.print("code7: \007");
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delay(ShortDelay);
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// Another nifty trick is that you can modify custom characters on the
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// display without having to re-write the characters on the display.
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// To do this, simply create a new character for a codepoint.
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// All characters on the display which have that codepoint will "magically"
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// change to the new custom character.
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// So for example, if the entire display was written with custom character
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// zero and character zero was a bell, if you called createChar() to
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// redefine character codepoint zero to be a duck,
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// the entire display would turn to ducks without having to send any
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// characters to the display.
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// create the initial custom character
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lcd.createChar(0, bell);
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// fill the custom character line with the custom character.
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lcd.setCursor(0,customcharRow);
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for(uint8_t col=0; col<LCD_COLS; col++)
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lcd.write(0);
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delay(ShortDelay);
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// change the single custom character previously written on the row
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// and all the characters on the row will change
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// without having to re-write the characters.
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lcd.createChar(0, note);
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delay(ShortDelay);
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lcd.createChar(0, clockface);
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delay(ShortDelay);
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lcd.createChar(0, heart);
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delay(ShortDelay);
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lcd.createChar(0, duck);
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delay(ShortDelay);
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lcd.createChar(0, check);
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delay(ShortDelay);
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lcd.createChar(0, cross);
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delay(ShortDelay);
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lcd.createChar(0, smile);
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delay(ShortDelay);
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lcd.createChar(0, degreeSymbol);
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delay(ShortDelay);
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lcd.createChar(0, degreeC);
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delay(ShortDelay);
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lcd.createChar(0, degreeF);
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delay(ShortDelay);
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// show multiple vertical bars rising
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// by changing the single custom character that is already written
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// to the entire row on the display
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for(int i = 0; i < 9; i++)
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{
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lcd.createChar(0, vsigbar[i]);
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delay(ShortDelay);
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}
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delay(LongDelay);
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}
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