#include <SPI.h>

// Pin definitions 
#define CS_PIN   7
//#define SCLK_PIN 9
//#define MISO_PIN 8
//#define MOSI_PIN 10
#define reset_PIN 5     // Reset Pin

void setup() { 
  Serial.begin(115200);
  while (!Serial);

  // Chip Select pin
  pinMode(CS_PIN, OUTPUT);
  digitalWrite(CS_PIN, HIGH);

  // Configure reset pin
  pinMode(reset_PIN, OUTPUT);
  digitalWrite(reset_PIN, HIGH); // reset ADC

  // Initialize SPI using Mode 1 (CPOL=0, CPHA=1)
  SPI.begin();

  // Send Software reset before the first communication
  resetADC();

  // Read and print multiple registers
  uint16_t deviceID = readRegister(0x03); // Device ID register
  Serial.print("Device ID (0x04): 0x");
  Serial.println(deviceID, HEX);

  uint16_t status = readRegister(0x01); // Status register
  Serial.print("Status Register (0x01): 0x");
  Serial.println(status, HEX);

  // Read back register 0x05 to verify communication
  uint16_t regVal = readRegister(0x02);
  Serial.print("Register (0x05): 0x");
  Serial.println(regVal, HEX);

}

void loop() {
  //Test to read the second channel (result= 66535(0XFFFF))
  //uint16_t rawValue = readChannel(2);
  //Serial.print("ADC-Wert Ch2: ");
  //Serial.println(rawValue);
  delay(1000);
}


// Sends a software reset command (0x8500) to ADS8684

void resetADC() {
  digitalWrite(CS_PIN, LOW);
  SPI.transfer16(0x8500);  
  digitalWrite(CS_PIN, HIGH);
  delay(10);  // Give device time to reset
}

uint16_t readRegister(uint8_t regAddr) {
  uint16_t command = (regAddr << 8);
  SPI.beginTransaction(SPISettings(1000000, MSBFIRST, SPI_MODE1));
  digitalWrite(CS_PIN, LOW);
  SPI.transfer16(command); 
  digitalWrite(CS_PIN, HIGH);
  digitalWrite(CS_PIN, LOW);
  uint16_t data = SPI.transfer16(0x0000);  // Dummy write to read
  digitalWrite(CS_PIN, HIGH);

  return data;
}

/*
uint8_t readRegister(uint8_t reg) {
    SPI.beginTransaction(SPISettings(1000000, MSBFIRST, SPI_MODE1));
    digitalWrite(CS_PIN, LOW);
    SPI.transfer((reg << 1) | 0x00);
    SPI.transfer(0x00);
    byte result = SPI.transfer(0x00);
    digitalWrite(CS_PIN, HIGH);
    SPI.endTransaction();
    return result;
    }
*/


uint16_t readChannel(uint8_t channel) {
  uint16_t command = 0xC000 | ((channel & 0x0F) << 8);
  digitalWrite(CS_PIN, LOW);
  uint16_t rawData = SPI.transfer16(command);
  digitalWrite(CS_PIN, HIGH);

  return rawData;
}