FDC2214EVM: Problems to start the I²C Bus.

Connection:

ESP32 <--> FDC2214EVM

• GND <--> GND
• 3.3V <--> 3.3V
• GPIO21 <--> SDA
• GPIO22 <--> SCL

My problem is that if i start the ESP32 normally the communication via I²C should start. But it is not working. I am using the FDC2214EVM without the USB-Part and without the 2 sensor areas. I am only using the breakout board with 4-channels. The funny thing is that it works when I reset my ESP32 microcontroller and put my finger on the SDA pin and the SCL pin at the same time. Probably the I²C bus will be short circuited for a short moment. 

Additonally i am using the Arduino IDE to flash my ESP32 and for the FDC2214EVM i am using the LIb from https://github.com/zharijs/FDC2214.

My Code for the ESP32 is the following:

#include <Wire.h>
#include "FDC2214.h"

FDC2214 capsense(FDC2214_I2C_ADDR_0); // Use FDC2214_I2C_ADDR_1

byte FDC = 0x2A;// FDC address either 0x2A or 0x2B;
int altzeit, delayzeit = 250;
int g = 0; // Channel auf dem FDC2214
unsigned long capacity; // Value from Sensor-FDC2214

void setup() {
  Serial.begin(115200);
  Wire.begin();
  //Wire.setClock(100000);
  Configure();
  Wire.beginTransmission(FDC); 
}

void loop() {
  if (millis() - altzeit > delayzeit) {
    altzeit = millis();
    capacity = capsense.getReading28(g);// Befehl zum Lesen der Kapa.
    if (capacity > 0) {
      Serial.println(capacity);
    }
  }
  delay(20);
}

//Configuring the FDC2214
void writeConfig(int FDC, byte reg, byte MSB, byte LSB) {
  Wire.beginTransmission(FDC);
  Wire.write(reg);
  Wire.write(MSB);
  Wire.write(LSB);
  Wire.endTransmission();
}

void Configure() {
  // based on best results with the TI demo program
  writeConfig(FDC, 0x1C, 0x80, 0x00); //Reset

  writeConfig(FDC, 0x08, 0xFF, 0xFF);
  writeConfig(FDC, 0x09, 0xFF, 0xFF);
  writeConfig(FDC, 0x0A, 0xFF, 0xFF);

  writeConfig(FDC, 0x10, 0x04, 0x00);
  writeConfig(FDC, 0x11, 0x04, 0x00);
  writeConfig(FDC, 0x12, 0x04, 0x00);

  writeConfig(FDC, 0x14, 0x10, 0x01);
  writeConfig(FDC, 0x15, 0x10, 0x01);
  writeConfig(FDC, 0x16, 0x10, 0x01);

  writeConfig(FDC, 0x19, 0x00, 0x01);//ERROR_CONFIG 

  writeConfig(FDC, 0x1B, 0xC2, 0x0C);//MUX_CONFIG 

  writeConfig(FDC, 0x1E, 0x88, 0x00);
  writeConfig(FDC, 0x1F, 0x88, 0x00);
  writeConfig(FDC, 0x20, 0x88, 0x00);

  writeConfig(FDC, 0x1A, 0x1E, 0x01);//CONFIG 

  //writeConfig(FDC, 0x17, 0x10, 0x01);//CLOCK_DIVIDERS_CH3
  //writeConfig(FDC, 0x21, 0x88, 0x00);//DRIVE_CURRENT_CH3
  //writeConfig(FDC, 0x13, 0x04, 0x00);//SETTLECOUNT_CH3
  //writeConfig(FDC, 0x0B, 0xFF, 0xFF);//RCOUNT_CH3
}