#include <SPI.h>

#define PIN_SCK          52             // SPI clock 74HC595 pin 11 and 4021 pin 10
#define PIN_MISO         50             // SPI data input 4021 pin 3
#define PIN_MOSI         51             // SPI data output 74HC595 pin 14
#define PIN_SS1          48             // SPI hardware default SS pin, 4021 pin 9
#define PIN_595_1        46             // SPI 74HC595 pin 12

void setup() {
  Serial.begin(9600);
  SPI.begin();

  digitalWrite(PIN_SS1, HIGH);
  pinMode(PIN_595_1, OUTPUT);
  digitalWrite(PIN_595_1, HIGH);
}

void loop() {
  testleds();
  testbuttons();
}

void testleds() {
  byte sas =        B00000001;
  byte maneuver =   B00000010;
  byte prograde =   B00000100;
  byte retrograde = B00001000;
  byte normal =     B00010000;
  byte antinormal = B00100000;
  byte radial_out = B01000000;
  byte radial_in =  B10000000;

  byte target =     B00000001;
  byte antitarget = B00000010;

  byte on =         B11111111;
  byte off =        B00000000;

  //turn sas on for 3 secs
  digitalWrite(PIN_595_1, LOW);
  SPI.transfer(sas);
  delay(3000);
  SPI.transfer(off);
  SPI.transfer(off);
  digitalWrite(PIN_595_1, HIGH);
}

void testbuttons() {

}