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https://github.com/witnessmenow/ESP32-Cheap-Yellow-Display.git
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123 lines
3.5 KiB
C++
123 lines
3.5 KiB
C++
/*******************************************************************
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An Example showing how the backlight of the CYD display can be controlled
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This is adapted from the ESP32 example "LEDC Software Fade"
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https://github.com/witnessmenow/ESP32-Cheap-Yellow-Display
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If you find what I do useful and would like to support me,
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please consider becoming a sponsor on Github
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https://github.com/sponsors/witnessmenow/
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Written by Brian Lough
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YouTube: https://www.youtube.com/brianlough
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Twitter: https://twitter.com/witnessmenow
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*******************************************************************/
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// Make sure to copy the UserSetup.h file into the library as
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// per the Github Instructions. The pins are defined in there.
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#include <TFT_eSPI.h>
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// A library for interfacing with LCD displays
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//
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// Can be installed from the library manager (Search for "TFT_eSPI")
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//https://github.com/Bodmer/TFT_eSPI
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TFT_eSPI tft = TFT_eSPI();
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#define LCD_BACK_LIGHT_PIN 21
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// use first channel of 16 channels (started from zero)
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#define LEDC_CHANNEL_0 0
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// use 12 bit precission for LEDC timer
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#define LEDC_TIMER_12_BIT 12
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// use 5000 Hz as a LEDC base frequency
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#define LEDC_BASE_FREQ 5000
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// Arduino like analogWrite
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// value has to be between 0 and valueMax
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void ledcAnalogWrite(uint8_t channel, uint32_t value, uint32_t valueMax = 255) {
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// calculate duty, 4095 from 2 ^ 12 - 1
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uint32_t duty = (4095 / valueMax) * min(value, valueMax);
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// write duty to LEDC
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ledcWrite(channel, duty);
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}
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void setup() {
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Serial.begin(115200);
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// Start the tft display and set it to black
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tft.init();
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// Setting up the LEDC and configuring the Back light pin
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// NOTE: this needs to be done after tft.init()
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#if ESP_IDF_VERSION_MAJOR == 5
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ledcAttach(LCD_BACK_LIGHT_PIN, LEDC_BASE_FREQ, LEDC_TIMER_12_BIT);
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#else
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ledcSetup(LEDC_CHANNEL_0, LEDC_BASE_FREQ, LEDC_TIMER_12_BIT);
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ledcAttachPin(LCD_BACK_LIGHT_PIN, LEDC_CHANNEL_0);
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#endif
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tft.setRotation(1); //This is the display in landscape
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// Clear the screen before writing to it
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tft.fillScreen(TFT_BLACK);
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tft.setTextColor(TFT_WHITE, TFT_BLACK);
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int x = 5;
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int y = 10;
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int fontSize = 2;
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tft.drawString("Hello", x, y, fontSize); // Left Aligned
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x = 320 / 2;
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y += 16;
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tft.setTextColor(TFT_BLUE, TFT_BLACK);
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tft.drawCentreString("World", x, y, fontSize);
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// Simple on off control
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ledcAnalogWrite(LEDC_CHANNEL_0, 255); // On full brightness
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delay(1000);
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ledcAnalogWrite(LEDC_CHANNEL_0, 0); // Off
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delay(1000);
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// --------------- Digital Write ----------------
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// NOTE: you could use digitalWrite if you only want to
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// turn the display on or off
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// You would use this instead of any "ledc" code
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//pinMode(LCD_BACK_LIGHT_PIN, OUTPUT); // set pin as output
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// This will turn back light off
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//digitalWrite(LCD_BACK_LIGHT_PIN, HIGH);
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//delay(1000);
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// This will turn the back light on (full brightness)
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//digitalWrite(LCD_BACK_LIGHT_PIN, LOW);
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//-------------------------------------------------
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}
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int brightness = 0; // how bright the LED is
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int fadeAmount = 5; // how many points to fade the LED by
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// Fade the display between bright and dark
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void loop() {
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// set the brightness on LEDC channel 0
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ledcAnalogWrite(LEDC_CHANNEL_0, brightness);
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// change the brightness for next time through the loop:
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brightness = brightness + fadeAmount;
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// reverse the direction of the fading at the ends of the fade:
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if (brightness <= 0 || brightness >= 255) {
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fadeAmount = -fadeAmount;
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}
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// wait for 30 milliseconds to see the dimming effect
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delay(30);
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}
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