ESP8266 Community Forum

- Wed Aug 01, 2018 3:00 pm #77530 Hi,

I'm new here and have a question

I have connected the WaveShare 1.54" ePaper Display to a ESP-12F (NodeMCU) according to the schematic.
BUSY->D6(MISO), RST->D4, DC->D3, CS->D8(SS), CLK->D5(SCK), DIN->D7(MOSI), GND->GNG, 3.3V->3.3V

My sample code(see below) only works, if I disconnect pin D8 (CS) during startup of the Board (after pressing Reset) and reconnect it afterwards. If I leave it connected and try to reset the board, I only get

Code: Select all ets Jan  8 2013,rst cause:2, boot mode:(7,6)

waiting for host


in the Serial Monitor. What could be the problem here? I already tried a beefy power supply, but that doesn't make any difference. Maybe you can help me

Here is the Code:

Code: Select all#include <GxEPD.h>
#include <GxGDEP015OC1/GxGDEP015OC1.cpp> // for the 1.54 inch display module
#include <GxIO/GxIO_SPI/GxIO_SPI.cpp>
#include <GxIO/GxIO.cpp>
 
// ESP8266 generic/common.h
//static const uint8_t SS    = 15;
//static const uint8_t MOSI  = 13;
//static const uint8_t SCK   = 14;
 
GxIO_Class io(SPI, SS/* CS */,  D3/* DC */,  D4/* RST */);
GxEPD_Class display(io, /*RST=D4*/ 2, /*BUSY=D2*/ -1);
 
// FreeFonts from Adafruit_GFX
 
#include <Fonts/FreeSansBold12pt7b.h>
#include <Fonts/FreeSansBold18pt7b.h>
#include <Fonts/FreeSansBold24pt7b.h>

int counter = 100;
void setup()
{
  delay(1000);
  Serial.begin(115200);
  while (!Serial) { }
  Serial.println();
  Serial.println("setup");
  delay(1000);
  SPI.setFrequency(8000000L);
  display.init();
}

void loop()
{
  sendUpdateBME280();
  delay(10000);
}
 
void sendUpdateBME280()
{
  Serial.println("Update");
  delay(1000);
  uint16_t middleY = display.height() / 2;
  display.setRotation(1);
  display.fillScreen(GxEPD_WHITE);
  display.setTextColor(GxEPD_BLACK);
  display.setFont(&FreeSansBold24pt7b);
  display.setTextSize(2);
  display.setCursor(8, 72);
  display.print(counter, 1);

  display.update();
  counter++;
}

- Thu Aug 02, 2018 4:18 pm #77551 D8 on a NODEMCU is GPIO15.

GPIO15 must be low during boot for the ESP8266 to enter normal run mode. If it is high then it enters Serial programming mode for a new program to be uploaded. So I think the display is preventing the default low condition on start up.

Use a different pin for the CS