i2cdetect没有显示任何地址

Question

我使用的是带有NodeMCU ESP8266的OLED 128*64显示屏。当我试图检测屏幕地址时，串行监视器显示：在这里输入图像描述

如果有人能告诉我问题出在哪里，那就太好了？怎么解决不了？

Answer 1

嗨，Mari，请试试这个I2c测试器:它会告诉你设备的数量和地址。

#include <Wire.h>

byte errorResult;           // error code returned by I2C 
byte i2c_addr;              // I2C address being pinged
byte lowerAddress = 0x08;   // I2C lowest valid address in range
byte upperAddress = 0x77;   // I2C highest valid address in range
byte numDevices;            // how many devices were located on I2C bus

void setup() {
  Wire.begin();             // I2C init
  Serial.begin(115200);       // search results show up in serial monitor
}

void loop() {
    if (lowerAddress < 0x10)                                // pad single digit addresses with a leading "0"
  Serial.print("0");
  Serial.print(lowerAddress, HEX);
  Serial.print(" to 0x");
  Serial.print(upperAddress, HEX);
  Serial.println(".");

  numDevices = 0;

  for (i2c_addr = lowerAddress; i2c_addr <= upperAddress; i2c_addr++ ) 
    // loop through all valid I2C addresses
  {
    Wire.beginTransmission(i2c_addr);                     // initiate communication at current address
    errorResult = Wire.endTransmission();                 // if a device is present, it will send an ack and "0" will be returned from function

    if (errorResult == 0)                                 // "0" means a device at current address has acknowledged the serial communication
    {
      Serial.print("I2C device found at address 0x");

      if (i2c_addr < 0x10)                                // pad single digit addresses with a leading "0"
        Serial.print("0");

      Serial.println(i2c_addr, HEX);                      // display the address on the serial monitor when a device is found
      numDevices++;
    }
  }

  Serial.print("Scan complete.  Devices found: ");
  Serial.println(numDevices);
  Serial.println();

  delay(10000);                                           // wait 10 seconds and scan again to detect on-the-fly bus changes
}

Answer 2

接线应用于I2C连接: D2 -> SDA、D1 -> SCL、GND -> GND、(*) -> Vcc。

(*)检查您的oled型号，一些工作在+5V，另一些工作在+3.3V，这可能是一个问题，而且通常不需要拔起电阻(检查您的型号规格)也检查您的oled的规格，有时需要一些跳线装置。

Answer 3

我发现了问题:我没有正确地插入板内的nodemcu。