ESP32-PICO-D4 ST7735 180x60 deep sleep

[biccius]

Hi,

I'm programming a LilyGo T-Wristband with Arduino core (no esp-idf) using ESP32-PICO-D4.
A ST7735 0.96" 160x80 TFT screen is connected using SPI and TFT_eSPI is the graphical library used to manage the display.
A TP button is used to wake up the chip from deep sleep mode.
Schematics and more informations are at the end of this post.

My purpose is to try to:

a. init display at the start then fill the screen with a color A
b. send the esp32 to deep sleep
c. wake up with button press the esp32 and redraw the display with color A avoiding to re-initialize the display cause it's already set
d. then change in progression colors to B, C , etc..

On "c" phase i don't want to re-initialize the display everytime i wake from a deep sleep because is a slow operation.
I assume the display is already initialized and just wake it up from sleep as fast as possible.
So i'm trying with this code to keep the RESET pin high (gpio_hold_en) and switch off the display (DISPOFF) and sending it to sleep (SLPIN)-

Code: Select all

#include <TFT_eSPI.h>            
#include <SPI.h>
#include <WiFi.h>
#include <Wire.h>
#include "sensor.h"
#include "esp_adc_cal.h"


#define TP_PIN_PIN          		33		// wakeup pin
#define TP_PWR_PIN 			25		// power for the touch button

TFT_eSPI tft = TFT_eSPI();       // Invoke library, pins defined in User_Setup.h
RTC_DATA_ATTR int boots = 0;


void setupTFT()
{
  tft.init();
  tft.setRotation(1);
  tft.setSwapBytes(true);
}


int color = 0x5555;


void Wake()
{

    pinMode(TFT_CS, OUTPUT);
    pinMode(TFT_DC, OUTPUT);
    pinMode(TFT_BL, OUTPUT);

    digitalWrite( TFT_BL , HIGH);	//backlight on

    SPI.begin(TFT_SCLK, TFT_MISO, TFT_MOSI, -1);

    tft.writecommand(ST7735_DISPON);	// display on
    delay(150);
    tft.writecommand(ST7735_SLPOUT);	// display sleep off
    delay(150);
}

void Sleep()
{
  tft.writecommand(ST7735_SLPIN);  // display sleep on
  delay(150);
  tft.writecommand(ST7735_DISPOFF);  // display off
  delay(200);

  digitalWrite(GPIO_NUM_26, HIGH);  	// keep GPIO_26 high state after deep sleep reset
  gpio_hold_en(GPIO_NUM_26);		// display is preserved
  gpio_deep_sleep_hold_en();

  digitalWrite( TFT_BL , LOW);  //backlight off
  SPI.end();	// spi communication stopped

  esp_sleep_enable_ext1_wakeup(GPIO_SEL_33, ESP_EXT1_WAKEUP_ANY_HIGH);
  esp_deep_sleep_start();
}


void setup(void)
{
	  pinMode(TP_PIN_PIN, INPUT);
	  pinMode(TP_PWR_PIN, PULLUP);
	  //! Must be set to pull-up output mode in order to wake up in deep sleep mode
	  digitalWrite(TP_PWR_PIN, HIGH);

	  Serial.begin(115200);

	  if(boots == 0) //Run this only the first time
	  {
		  Serial.println("first boot");
		  setupTFT();
		  tft.fillScreen(color);
		  color+=0x1000;
	  	  boots ++;
	  }
	  else
	  {
		  Serial.println("wake");
		  Wake();
		  tft.setRotation(1);
		  tft.setSwapBytes(1);
		  delay(3000);
		  while (1)
		  {
			  Serial.println("changing color");
			  tft.fillScreen(color);
			  color+=10;
			  delay(10);
		  }
	  }//if boots
}


void loop()
{
	delay(5000);
	Serial.println("sleep");
	Sleep();
}

Code seems to work properly but in "d" phase i get the display not full filled by a new color like in figure:



Is there something wrong?
What can be the cause and how to fix it?

Thank you


PIN DEFINITION

• TFT_MOSI 19

• TFT_SCLK 18

• TFT_CS 5

• TFT_DC 23

• TFT_RST 26

• TFT_BL 27

• Touchpad 33

• Touchpad Power 25

RESOURCES

• LilyGo T-Wristband : https://github.com/Xinyuan-LilyGO/LilyGo-T-Wristband/

• Schematics: https://github.com/Xinyuan-LilyGO/LilyG ... 200306.pdf

• Issue description: https://github.com/Xinyuan-LilyGO/LilyG ... /issues/19