The code below is the one I am using, it uses sdFat. The wiring is correct because it did not have any problems initializing it.
#include <Wire.h>
#include <Adafruit_INA219.h>
#include <Adafruit_SSD1306.h>
#include <SPI.h>
#include “SdFat.h”
SdFat SD;
#define OLED_RESET 4
Adafruit_SSD1306 display(OLED_RESET);
Adafruit_INA219 ina219;
unsigned long previousMillis = 0;
unsigned long interval = 100;
const int chipSelect = 10;
float shuntvoltage = 0;
float busvoltage = 0;
float current_mA = 0;
float loadvoltage = 0;
float energy = 0;
File TimeFile;
File VoltFile;
File CurFile;
void setup() {
SD.begin(chipSelect);
display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
ina219.begin();
}
void loop() {
unsigned long currentMillis = millis();
if (currentMillis - previousMillis >= interval)
{
previousMillis = currentMillis;
ina219values();
TimeFile = SD.open(“TIME.txt”, FILE_WRITE);
if (TimeFile) {
TimeFile.println(currentMillis);
TimeFile.close();
}
VoltFile = SD.open(“VOLT.txt”, FILE_WRITE);
if (VoltFile) {
VoltFile.println(loadvoltage);
VoltFile.close();
}
CurFile = SD.open(“CUR.txt”, FILE_WRITE);
if (CurFile) {
CurFile.println(current_mA);
CurFile.close();
}
displaydata();
}
}
void displaydata() {
display.clearDisplay();
display.setTextColor(WHITE);
display.setTextSize(1);
display.setCursor(0, 0);
display.println(loadvoltage);
display.setCursor(35, 0);
display.println(“V”);
display.setCursor(50, 0);
display.println(current_mA);
display.setCursor(95, 0);
display.println(“mA”);
display.setCursor(0, 10);
display.println(loadvoltage * current_mA);
display.setCursor(65, 10);
display.println(“mW”);
display.setCursor(0, 20);
display.println(energy);
display.setCursor(65, 20);
display.println(“mWh”);
display.display();
}
void ina219values() {
shuntvoltage = ina219.getShuntVoltage_mV();
busvoltage = ina219.getBusVoltage_V();
current_mA = ina219.getCurrent_mA();
loadvoltage = busvoltage + (shuntvoltage / 1000);
energy = energy + loadvoltage * current_mA / 3600;
}