| /* | |
| Demonstration sketch for Adafruit LCD backpack | |
| using MCP23008 I2C expander | |
| Uses the ATTiny 85 (replaces Trinket below) | |
| The circuit: | |
| * 5V to Arduino 5V pin | |
| * GND to Arduino GND pin | |
| * Display i2c backpack CLK to Trinket GPIO #2 (Arduino pin 2/attiny85 pin 7) | |
| * Display i2c backpack DAT to Trinket GPIO #0 (Arduino pin 0/attiny85 pin 5) | |
| If not visible at first, adjust contrast using screw crontrol on back | |
| example adapted from | |
| - https://github.com/adafruit/TinyLiquidCrystal/blob/master/examples/HelloWorld_i2c/Trinket_HelloWorld_i2c.ino | |
| - https://github.com/adafruit/TinyLiquidCrystal/blob/master/examples/Trinket_DHT_LCD/Trinket_DHT_LCD.ino | |
| ATTiny Core settings in Arduino, using "Arduino as ISP". | |
| Run "Burn bootloader" before uploading sketch the first time. | |
| - Board: "ATtiny25/45/85 | |
| - Chip: "ATtiny85" | |
| - Clock: "8 MHz (internal) | |
| - B.O.D.: "B.O.D. Disabled" | |
| - LTO (1.6.11+ only): "Disabled" | |
| - Timer 1 Clock: "CPU" | |
| */ | |
| // include the library code | |
| #include <TinyWireM.h> // Wire/I2C library for ATtiny85 | |
| #include <TinyLiquidCrystal.h> | |
| #include <avr/power.h> // needed to up clock to 16 MHz on 5v Trinket | |
| // Connect display via i2c, default address #0 (A0-A2 not jumpered) | |
| TinyLiquidCrystal lcd(0); | |
| int16_t t; // loop count | |
| void setup() { | |
| // put your setup code here, to run once: | |
| if (F_CPU == 16000000) clock_prescale_set(clock_div_1); // 5V Trinket: run at 16 MHz | |
| lcd.begin(16, 2); // set up the LCD's number of rows and columns: | |
| lcd.setBacklight(HIGH); // Set backlight | |
| lcd.print("hello, world!"); // Print a message to the LCD. | |
| } | |
| void loop() { | |
| // put your main code here, to run repeatedly: | |
| lcd.setCursor(0, 0); | |
| lcd.print("Bad read on DHT"); // print error message | |
| // set the cursor to column 0, line 1 | |
| // (note: line 1 is the second row, since counting begins with 0): | |
| lcd.setCursor(0, 1); | |
| // print the number of seconds since reset: | |
| lcd.print(millis()/1000); | |
| delay(2000); // cycles LCD backlight every four seconds (2000 ms * 2) | |
| t++; | |
| if (t % 2) { | |
| lcd.setBacklight(HIGH); // Set backlight | |
| } else { | |
| lcd.setBacklight(LOW); // Set backlight | |
| } | |
| } |
i2c/SPI LCD backpack https://www.adafruit.com/product/292
ATtiny85 Pinout
https://github.com/adafruit/Adafruit_LiquidCrystal -> https://github.com/adafruit/TinyLiquidCrystal.git
Used Arduino Library Manager to install "TinyLiquidCrystal" and "TinyWireM" library
