Interfacing ADS8319 with Arduino UNO


I am using Arduino UNO and trying to interface 2 ADS8319 ADCs with it via the SPI interface. The ADCs data sheet can be found here :

I have interfaced the 2 ADCs with the micro-controller using the “4 Wire CS Mode Without Busy Indicator” (data sheet page number 15).

I have attached my circuit schematic screen shot.

I am using the following code to get the values from the ADCs

#include <SPI.h>
#define CONVPIN 7
#define SELPIN 8
#define SELPIN2 4
#define MISOPIN 12
#define SCLKPIN 13

int adcvalue;
byte byte1; 
byte byte2;
const float aRefVoltage = 5;
float volts = 0;

void setup() {
  // put your setup code here, to run once:
pinMode(SELPIN, OUTPUT); // ADC's selection pin
pinMode(SELPIN2, OUTPUT); // 2nd ADC's selection pin
pinMode(CONVPIN, OUTPUT); // ADC's conversion pin
pinMode(SCLKPIN, OUTPUT); // ADC's clock pin
pinMode(MISOPIN, INPUT);  // ADC's data out

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(CONVPIN, LOW);
digitalWrite(SELPIN, HIGH);
digitalWrite(SELPIN2, HIGH);
digitalWrite(CONVPIN, HIGH);
digitalWrite(SELPIN, LOW);
digitalWrite(SELPIN2, LOW);


byte1 = SPI.transfer(0x00); //transfer (read) 8 bits from the adc chip D15-8
byte2 = SPI.transfer(0x00);  //transfer (read) the second 8 bits. D7-0

adcvalue = (byte1 <<8) | (byte2 & 0xff);  // combine the 2 bytes to make our 16 bit word
Serial.print("Voltage Value: ");
volts = (adcvalue*aRefVoltage/65535);
Serial.print(" Sensor Volts: ");

However i am not getting the right values. The values keep on changing in between 0 and 2.4 V .I am not sure if my code is correct or not. Can you please verify the code so that i should know whether the problem is in my hardware, or the code.