// Test for minimum program size.  
// Edit AVRI2C_FASTMODE in SSD1306Ascii.h to change the default I2C frequency.  
  
#include "SSD1306Ascii.h"  
#include "SSD1306AsciiAvrI2c.h"  
  
// 0X3C+SA0 - 0x3C or 0x3D  
#define I2C_ADDRESS 0x3C  

// 電壓參數
const int analogPin = A0;   // 模擬輸入引腳
const float referenceVoltage = 5.0;  // Arduino 的參考電壓 (5V)
const float voltageDividerRatio = 3.0;  // 假設使用分壓器減少電壓到1/3 (15V -> 5V)

// 最大最小電壓初始化
float maxVoltage = 0.0;
float minVoltage = 15.0;

// Define proper RST_PIN if required.  
#define RST_PIN -1  

#define IO8 8 // using IO as load control 
 
SSD1306AsciiAvrI2c oled;  
int analogValue = 0; //value of the voltage, raw format  
float voltage = 0; //voltage in edited format  
//------------------------------------------------------------------------------  
void setup() {  
#if RST_PIN >= 0  

  //oled.begin(&Adafruit128x64, I2C_ADDRESS, RST_PIN);  

#else // RST_PIN >= 0  

  oled.begin(&Adafruit128x32, I2C_ADDRESS);  

#endif // RST_PIN >= 0  

  // Call oled.setI2cClock(frequency) to change from the default frequency.  

  //oled.setFont(CalLite24);
  oled.setFont(Callibri11);
  oled.clear();  
  //oled.println("0 V");  
  //oled.println("0 mA"); 
}  

void loadon() 
{ 
  pinMode(IO8, OUTPUT); 
  digitalWrite(IO8, LOW); 
} 

void loadoff() 
{ 
  pinMode(IO8, INPUT); 
} 

float value2voltage(int analogValue) {  
  voltage = 0.0048 * analogValue;  
  return voltage;  
}  

//------------------------------------------------------------------------------  
void loop() {
  //oled.clear();  
  oled.home(); 
  //delay(1000);

    // 讀取模擬引腳的值
  int analogValue = analogRead(analogPin);
  
  // 將模擬值轉換成實際電壓值
  float measuredVoltage = (analogValue * referenceVoltage / 1023.0) * voltageDividerRatio;
  
  // 更新最大最小電壓
  if (measuredVoltage > maxVoltage) {
    maxVoltage = measuredVoltage;
  }
  
  if (measuredVoltage < minVoltage) {
    minVoltage = measuredVoltage;
  }


  oled.print("V: ");
  oled.print(measuredVoltage);
  oled.println("V   ");  // 用空格清除多餘字符

  oled.print("Max: ");
  oled.print(maxVoltage);
  oled.print("V   ");

  oled.print("Min: ");
  oled.print(minVoltage);
  oled.println("V   ");  

  delay(500);

}