196 lines
6.7 KiB
C++
196 lines
6.7 KiB
C++
// vi:ts=4
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// ----------------------------------------------------------------------------
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// LineWrap - simple demonstration of automatic linewrap functionality
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// Created by Bill Perry 2020-06-26
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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 LCD devices like the Tsingtek Display HC1627 modules
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// in i2c mode. Devices such as HC1627-B-LWH-I2C-30 or HC1627-SYH-I2C-30
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// These devices have a native I2C interface rather than use a simple I2C
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// i/o expander chip such as a PCF8574 or MCP23008.
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//
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// NOTE:
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// These devices usually need external pullups as they typically are not on
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// the module.
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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 hd44780 library automatic line wrapping functionality.
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//
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// Background:
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// hd44780 LCDs do not use linear continuous memory for the characters
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// on the lines on the display.
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// This means that simply sending continuous characters to the
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// display will not fill lines and wrap appropriately as might be expected.
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// The hd44780 library solves this issue by adding a line wrapping capability
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// in s/w that can be enabled & disabled.
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// This allows the host to send characters to the display continuously and they
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// will wrap to the next lower line when the end of the visible line has been
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// reached. When on the bottom line it will wrap back to the top line.
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//
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// (Configure LCD_COLS & LCD_ROWS if desired/needed)
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// Expected behavior of the sketch:
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// - display a banner announcing the test.
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// - print the configured LCD geometry
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// - print a long text string to demostrate automatic line wrapping
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// - print lots of characters (slowly) to show how the full wrapping works.
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// (loop)
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//
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// If initialization of the LCD fails and the arduino supports a built in LED,
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// the sketch will simply blink the built in LED with the initalization error
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// code.
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//
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// Special note for certain 16x1 displays:
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// Some 16x1 displays are actually a 8x2 display that have both lines on
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// a single line on the display.
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// If you have one of these displays, simply set the geometry to 8x2 instead
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// of 16x1.
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// In normal sketches, lineWrap() mode will allow this type of display to
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// properly function as a 16x1 display in that it will allow printing up to
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// 16 characters on the display without having to manually set the cursor
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// position to print the right characters on the half of the display.
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// However, when using this 8x2 display as a 16x1 display,
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// scrollDisplayLeft() and scrollDisplayRight() will not work as intended.
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// They will shift the two halves of the display rather than the entire display.
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// This is because the hd44780 chip is doing the shift and chip is hard coded
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// internally for two lines.
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// ----------------------------------------------------------------------------
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// While not all modules use the same pinout,
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// Be VERY careful and check your datasheet.
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//
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// This pin table is for the Tsingtek Display HC1627-SYH-I2C-30 or
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// HC1627-SYH-I2C-30 module when it is strapped for i2c mode operation
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//
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// pin 14 is the pin closest to the edge of the PCB
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// 14 - connect to gnd
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// 13 - connect to vcc
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// 12 - ID0 --- controls bit 1 of 7 bit i2c address, strap accordingly
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// 11 - ID1 --- controls bit 2 of 7 bit i2c address, strap accordingly
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// 10 - not connected
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// 9 - not connected
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// 8 - SCL
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// 7 - SDA
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// 6 - connect to gnd
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// 5 - connect to gnd
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// 4 - connect to gnd
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// 3 - Vo Contrast Voltage input
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// 2 - VCC (5v)
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// 1 - LCD gnd
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// 15 - Backlight Anode (+5v)
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// 16 - Backlight Cathode (Gnd)
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//
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// I2C IDx address table
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// ID1 ID0 ADDR
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// L L 0x38/0x39
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// L H 0x3A/0x3B
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// H L 0x3C/0x3D
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// H H 0x3E/0x3F
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//
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// library only needs to know the base address (the lower address)
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//
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// ----------------------------------------------------------------------------
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// include the needed headers.
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#include <Wire.h>
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#include <hd44780.h> // main hd44780 header
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#include <hd44780ioClass/hd44780_HC1627_I2C.h> // i2c LCD i/o class header
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// Note, i2c address can be specified or automatically located
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// If you wish to use a specific address comment out this constructor
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// and use the constructor below that specifies the address
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// declare the lcd object for auto i2c address location
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hd44780_HC1627_I2C lcd;
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//
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// manually enter base address of LCD.
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// Base Addresses
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// - 0x38, 0x3A, 0x3C, or 0x3E
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// declare i2c address and constructor for specified i2c address
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//const int i2c_addr = 0x38;
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//hd44780_HC1627_I2C lcd(i2c_addr); // use device at this address
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// LCD geometry
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// while 16x2 will work on most displays even if the geometry is different,
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// for actual wrap testing of a particular LCD it is best to use the correct
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// geometry.
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const int LCD_COLS = 16;
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const int LCD_ROWS = 2;
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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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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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// turn on automatic line wrapping
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// which automatically wraps lines to the next lower line and wraps back
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// to the top when at the bottom line
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// NOTE:
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// noLineWrap() can be used to disable automatic line wrapping.
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// _write() can be called instead of write() to send data bytes
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// to the display bypassing any special character or line wrap processing.
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lcd.lineWrap();
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}
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void loop()
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{
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lcd.clear();
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lcd.print("WrapTest");
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delay(2000);
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lcd.clear();
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//print the configured LCD geometry
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lcd.print(LCD_COLS);
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lcd.print("x");
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lcd.print(LCD_ROWS);
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delay(3000);
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lcd.clear();
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// print a long text string
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// without line wrapping enabled, the text would not wrap properly
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// to the next line.
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if(LCD_COLS == 8)
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lcd.print("A long text line");
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else
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lcd.print("This is a very long line of text");
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delay(3000);
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lcd.clear();
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// now print 2 full displays worth of characters to show
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// the full wrapping.
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lcd.cursor(); // turn on cursor so you can see where it is
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char c = '0'; // start at the character for the number zero
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for(int i = 2*LCD_COLS*LCD_ROWS; i; i--)
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{
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lcd.print(c++);
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delay(200); // slow things down to watch the printing & wrapping
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if(c > 0x7e) // wrap back to beginning of printable ASCII chars
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c = '!';
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}
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delay(3000);
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lcd.noCursor(); // turn off cursor
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}
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