/*
* This is an example sketch that shows how to toggle the display
* on and off at runtime to avoid screen burn-in.
*
* The sketch also demonstrates how to erase a previous value by re-drawing the
* older value in the screen background color prior to writing a new value in
* the same location. This avoids the need to call fillScreen() to erase the
* entire screen followed by a complete redraw of screen contents.
*
* Originally written by Phill Kelley. BSD license.
* Adapted for ST77xx by Melissa LeBlanc-Williams
*/
#include <Adafruit_GFX.h> // Core graphics library
#include <Adafruit_ST7735.h> // Hardware-specific library for ST7735
#include <Adafruit_ST7789.h> // Hardware-specific library for ST7789
#include <SPI.h>
#ifdef ADAFRUIT_HALLOWING
#define TFT_CS 39 // Hallowing display control pins: chip select
#define TFT_RST 37 // Display reset
#define TFT_DC 38 // Display data/command select
#define TFT_BACKLIGHT 7 // Display backlight pin
#elif defined(ARDUINO_FEATHER_ESP32) // Feather Huzzah32
#define TFT_CS 14
#define TFT_RST 15
#define TFT_DC 32
#elif defined(ESP8266)
#define TFT_CS 4
#define TFT_RST 16
#define TFT_DC 5
#else
// For the breakout board, you can use any 2 or 3 pins.
// These pins will also work for the 1.8" TFT shield.
#define TFT_CS 10
#define TFT_RST 9 // Or set to -1 and connect to Arduino RESET pin
#define TFT_DC 8
#endif
#define SerialDebugging true
// OPTION 1 (recommended) is to use the HARDWARE SPI pins, which are unique
// to each board and not reassignable. For Arduino Uno: MOSI = pin 11 and
// SCLK = pin 13. This is the fastest mode of operation and is required if
// using the breakout board's microSD card.
// For 1.44" and 1.8" TFT with ST7735 (including HalloWing) use:
Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);
// For 1.3", 1.54", and 2.0" TFT with ST7789:
//Adafruit_ST7789 tft = Adafruit_ST7789(TFT_CS, TFT_DC, TFT_RST);
// OPTION 2 lets you interface the display using ANY TWO or THREE PINS,
// tradeoff being that performance is not as fast as hardware SPI above.
//#define TFT_MOSI 11 // Data out
//#define TFT_SCLK 13 // Clock out
//Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_MOSI, TFT_SCLK, TFT_RST);
// connect a push button between ground and...
const uint8_t Button_pin = 2;
// color definitions
const uint16_t Display_Color_Black = 0x0000;
const uint16_t Display_Color_Blue = 0x001F;
const uint16_t Display_Color_Red = 0xF800;
const uint16_t Display_Color_Green = 0x07E0;
const uint16_t Display_Color_Cyan = 0x07FF;
const uint16_t Display_Color_Magenta = 0xF81F;
const uint16_t Display_Color_Yellow = 0xFFE0;
const uint16_t Display_Color_White = 0xFFFF;
// The colors we actually want to use
uint16_t Display_Text_Color = Display_Color_Black;
uint16_t Display_Backround_Color = Display_Color_Blue;
// assume the display is off until configured in setup()
bool isDisplayVisible = false;
// declare size of working string buffers. Basic strlen("d hh:mm:ss") = 10
const size_t MaxString = 16;
// the string being displayed on the SSD1331 (initially empty)
char oldTimeString[MaxString] = { 0 };
// the interrupt service routine affects this
volatile bool isButtonPressed = false;
// interrupt service routine
void senseButtonPressed() {
if (!isButtonPressed) {
isButtonPressed = true;
}
}
void displayUpTime() {
// calculate seconds, truncated to the nearest whole second
unsigned long upSeconds = millis() / 1000;
// calculate days, truncated to nearest whole day
unsigned long days = upSeconds / 86400;
// the remaining hhmmss are
upSeconds = upSeconds % 86400;
// calculate hours, truncated to the nearest whole hour
unsigned long hours = upSeconds / 3600;
// the remaining mmss are
upSeconds = upSeconds % 3600;
// calculate minutes, truncated to the nearest whole minute
unsigned long minutes = upSeconds / 60;
// the remaining ss are
upSeconds = upSeconds % 60;
// allocate a buffer
char newTimeString[MaxString] = { 0 };
// construct the string representation
sprintf(
newTimeString,
"%lu %02lu:%02lu:%02lu",
days, hours, minutes, upSeconds
);
// has the time string changed since the last tft update?
if (strcmp(newTimeString,oldTimeString) != 0) {
// yes! home the cursor
tft.setCursor(0,0);
// change the text color to the background color
tft.setTextColor(Display_Backround_Color);
// redraw the old value to erase
tft.print(oldTimeString);
// home the cursor
tft.setCursor(0,0);
// change the text color to foreground color
tft.setTextColor(Display_Text_Color);
// draw the new time value
tft.print(newTimeString);
// and remember the new value
strcpy(oldTimeString,newTimeString);
}
}
void setup() {
// button press pulls pin LOW so configure HIGH
pinMode(Button_pin,INPUT_PULLUP);
// use an interrupt to sense when the button is pressed
attachInterrupt(digitalPinToInterrupt(Button_pin), senseButtonPressed, FALLING);
#if (SerialDebugging)
Serial.begin(115200); while (!Serial); Serial.println();
#endif
// settling time
delay(250);
// ignore any power-on-reboot garbage
isButtonPressed = false;
#ifdef ADAFRUIT_HALLOWING
// HalloWing is a special case. It uses a ST7735R display just like the
// breakout board, but the orientation and backlight control are different.
tft.initR(INITR_HALLOWING); // Initialize HalloWing-oriented screen
pinMode(TFT_BACKLIGHT, OUTPUT);
digitalWrite(TFT_BACKLIGHT, HIGH); // Backlight on
#else
// Use this initializer if using a 1.8" TFT screen:
tft.initR(INITR_BLACKTAB); // Init ST7735S chip, black tab
// OR use this initializer (uncomment) if using a 1.44" TFT:
//tft.initR(INITR_144GREENTAB); // Init ST7735R chip, green tab
// OR use this initializer (uncomment) if using a 0.96" 180x60 TFT:
//tft.initR(INITR_MINI160x80); // Init ST7735S mini display
// OR use this initializer (uncomment) if using a 1.54" 240x240 TFT:
//tft.init(240, 240); // Init ST7789 240x240
// OR use this initializer (uncomment) if using a 2.0" 320x240 TFT:
//tft.init(240, 320); // Init ST7789 320x240
// SPI speed defaults to SPI_DEFAULT_FREQ defined in the library, you can override it here
// Note that speed allowable depends on chip and quality of wiring, if you go too fast, you
// may end up with a black screen some times, or all the time.
//tft.setSPISpeed(40000000);
#endif
// initialise the display
tft.setFont();
tft.fillScreen(Display_Backround_Color);
tft.setTextColor(Display_Text_Color);
tft.setTextSize(1);
// the display is now on
isDisplayVisible = true;
}
void loop() {
// unconditional display, regardless of whether display is visible
displayUpTime();
// has the button been pressed?
if (isButtonPressed) {
// yes! toggle display visibility
isDisplayVisible = !isDisplayVisible;
// apply
tft.enableDisplay(isDisplayVisible);
#if (SerialDebugging)
Serial.print("button pressed @ ");
Serial.print(millis());
Serial.print(", display is now ");
Serial.println((isDisplayVisible ? "ON" : "OFF"));
#endif
// confirm button handled
isButtonPressed = false;
}
// no need to be in too much of a hurry
delay(100);
}