// 25LC1024 1Mbit SPI interface
//
// Device pin connections:
// 1 = CS (Chip Select) (from Arduino)
// 2 = SO (Master In Slave Out) (from Arduino)
// 3 = +5V (WP) (from Arduino)
// 4 = 0V (Ground) (from Arduino)
// 5 = SI (Master Out Slave In) (from Arduino)
// 6 = SCK (from Arduino)
// 7 = +5V HOLD (from Arduino)
// 8 = +5V Vcc (from Arduino)
//
// This file uses the SPI library and produces higher oscillation rates than the manual methods
// for the Uno: SS/CS = pin 10, MOSI/SI = pin 11, SCK/clock = pin 13, MISO/SO = pin = 12
//

#define WRITE 2
#define READ  3
#define WREN  6

#include <SPI.h>

unsigned int data;
unsigned int address = 0;
unsigned int outval = 44;
byte invalue;

void setup()
{
  Serial.begin(9600);
  Serial.println("--------------");
  Serial.println(SS); // chip select
  Serial.println(MOSI); // master out, slave in
  Serial.println(MISO); // master in, slave out
  Serial.println(SCK); // clock
  Serial.println("--------------");

  // set up to match device datasheet
  SPI.setBitOrder(MSBFIRST);
  SPI.setDataMode(SPI_MODE0);
  SPI.setClockDivider(SPI_CLOCK_DIV2); // max clock is 20MHz, so can set high speed
  SPI.begin(); // sets up pin modes etc.

  // Enable writing
  digitalWrite(SS, LOW);
  SPI.transfer(WREN);
  digitalWrite(SS, HIGH);

  // Write One Value to One Address
  digitalWrite(SS, LOW);
  SPI.transfer(WRITE); // write instruction
  SPI.transfer((address >> 16) & 255);
  SPI.transfer((address >> 8) & 255);
  SPI.transfer(address & 255);
  SPI.transfer(outval);
  digitalWrite(SS, HIGH);

  delay(1000);

  // Read One Value from One Address
  digitalWrite(SS, LOW);
  SPI.transfer(READ); // read instruction
  SPI.transfer((address >> 16) & 255);
  SPI.transfer((address >> 8) & 255);
  SPI.transfer(address & 255);   // 3rd byte of address
  invalue = SPI.transfer(0);        // Clock out the data
  Serial.print("Read Data = ");
  Serial.println(invalue,DEC);

  digitalWrite(SS, HIGH);
}

void loop()
{

}