142 lines
4.3 KiB
C++
142 lines
4.3 KiB
C++
// vi:ts=4
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// ----------------------------------------------------------------------------
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// UpTime - simple demonstration of lcd
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// Created by Bill Perry 2017-05-11
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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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//
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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 will print "UpTime" on top row of lcd
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// and will print the amount of time since the Arduino has been reset
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// on the second row.
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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.
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//
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// NOTE:
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// If the sketch fails to produce the expected results, or blinks the LED,
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// run the included I2CexpDiag sketch to test the i2c signals and the LCD.
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#include <Wire.h>
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#include <hd44780.h> // main hd44780 header
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#include <hd44780ioClass/hd44780_I2Cexp.h> // i2c expander i/o class header
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hd44780_I2Cexp lcd; // declare lcd object: auto locate & config exapander chip
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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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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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// hd44780 has a fatalError() routine that blinks an led if possible
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// begin() failed so call fatalError() with the error code.
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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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// Print a message to the LCD
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lcd.print(" UpTime");
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if(LCD_ROWS < 2)
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delay(3000);
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}
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void loop()
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{
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static unsigned long lastsecs = -1; // pre-initialize with non zero value
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unsigned long secs;
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int status;
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secs = millis() / 1000;
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// see if 1 second has passed
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// so the display is only updated once per second
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if(secs != lastsecs)
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{
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lastsecs = secs; // keep track of last seconds
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// set the cursor position to column 0, row 1
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// note: row 1 is the second row from top,
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// since row counting begins with 0
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// if display has only 1 line, it will appear on that line
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status = lcd.setCursor(0, 1);
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if(status) // non zero status means it was unsuccesful
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{
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// setCursor() failed so call fatalError() with the error code.
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hd44780::fatalError(status); // does not return
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}
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// print uptime on lcd device: (time since last reset)
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PrintUpTime(lcd, secs);
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}
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}
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// PrintUpTime(outdev, secs) - print uptime in HH:MM:SS format
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// outdev - the device to send output
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// secs - the total number of seconds uptime
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//
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// This is a fancy output routine.
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// outdev is a Print class object which indicates
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// where the output should be sent.
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// PrintUpTime can be used with any object that uses the Print class.
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// This code works with Serial objects, as well as the the hd44780 lcd objects.
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// i.e. you can call with Serial: PrintUpTime(Serial, seconds);
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void PrintUpTime(Print &outdev, unsigned long secs)
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{
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unsigned int hr, mins, sec;
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// convert total seconds to hours, mins, seconds
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mins = secs / 60; // how many total minutes
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hr = mins / 60; // how many total hours
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mins = mins % 60; // how many minutes within the hour
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sec = secs % 60; // how many seconds within the minute
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// print uptime in HH:MM:SS format
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if(hr > 99)
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hr %= 100; // limit hr to 0-99
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// Print class does not support fixed width formatting
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// so insert a zero if number smaller than 10
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if(hr < 10)
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outdev.write('0');
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outdev.print((int)hr);
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outdev.write(':');
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if(mins < 10)
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outdev.write('0');
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outdev.print((int)mins);
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outdev.write(':');
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if(sec < 10)
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outdev.write('0');
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outdev.print((int)sec);
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}
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