BlueCarFirmware1.ino

//
// Pins Defined
//
#define RDY_0           2
#define REQUEST_0       3
#define SS_0            5
#define RDY_1           6
#define REQUEST_1       9
#define SS_1            10
#define RDY_2           11
#define REQUEST_2       12
#define SS_2            A0
#define RDY_3           A1
#define REQUEST_3       A2
#define SS_3            A3

#define RDY_PIN_0       0
#define REQUEST_PIN_0   1
#define SS_PIN_0        2
#define RDY_PIN_1       3
#define REQUEST_PIN_1   4
#define SS_PIN_1        5
#define RDY_PIN_2       6
#define REQUEST_PIN_2   7
#define SS_PIN_2        8
#define RDY_PIN_3       9
#define REQUEST_PIN_3   10
#define SS_PIN_3        11

#define NUM_I_PINS        8
#define NUM_O_PINS        4

typedef struct{
    uint8_t     id;
    uint8_t     hardwareVersion;
    uint8_t     softwareVersion;
    uint8_t     rdyPin;
    uint8_t     reqPin;
    uint8_t     ssPin;
} module;

const int iPins[NUM_I_PINS] = {RDY_0,REQUEST_0,RDY_1,REQUEST_1,RDY_2,REQUEST_2,RDY_3,REQUEST_3};
const int oPins[NUM_O_PINS] = {SS_0, SS_1, SS_2, SS_3};

int pinState[8] = {HIGH,HIGH,HIGH,HIGH,HIGH,HIGH,HIGH,HIGH};
int numConnectedModules = 0;

module modules[5] = {NULL,NULL,NULL,NULL,NULL};



// COMMON SETTINGS
// ----------------------------------------------------------------------------------------------
// These settings are used in both SW UART, HW UART and SPI mode
// ----------------------------------------------------------------------------------------------
#define BUFSIZE                        128   // Size of the read buffer for incoming data
#define VERBOSE_MODE                   true  // If set to 'true' enables debug output

// SHARED SPI SETTINGS
// ----------------------------------------------------------------------------------------------
// The following macros declare the pins to use for HW and SW SPI communication.
// SCK, MISO and MOSI should be connected to the HW SPI pins on the Uno when
// using HW SPI.  This should be used with nRF51822 based Bluefruit LE modules
// that use SPI (Bluefruit LE SPI Friend).
// ----------------------------------------------------------------------------------------------
#define BLUEFRUIT_SPI_CS               8
#define BLUEFRUIT_SPI_IRQ              7
#define BLUEFRUIT_SPI_RST              4    // Optional but recommended, set to -1 if unused



/*********************************************************************
 Blue Car Version 1

 MIT license, check LICENSE for more information
 All text above, and the splash screen below must be included in
 any redistribution

 Modified By Joel Simonoff November 2015 for BlueCar. Joels edits will
 be covered under the MIT License.
*********************************************************************/

#include <Arduino.h>
#include <SPI.h>
#include "Adafruit_BLE.h"
#include "Adafruit_BluefruitLE_SPI.h"

#define MODE_LED_BEHAVIOUR "MODE"
#define LED 13

Adafruit_BluefruitLE_SPI ble(BLUEFRUIT_SPI_CS, BLUEFRUIT_SPI_IRQ, BLUEFRUIT_SPI_RST);

void setup(void){
  pinMode(LED, OUTPUT);
  digitalWrite(LED, LOW);

  //while (!Serial);  // required for Flora & Micro
  delay(500);

  Serial.begin(115200);
  Serial.println(F("Adafruit Bluefruit Command <-> Data Mode Example"));
  Serial.println(F("------------------------------------------------"));

  /* Initialise the module */
  Serial.print(F("Initialising the Bluefruit LE module: "));

  if ( !ble.begin(VERBOSE_MODE) )
  {
    Serial.println(F("Couldn't find Bluefruit, make sure it's in CoMmanD mode & check wiring?"));
  }
  Serial.println( F("OK!") );

  /* Perform a factory reset to make sure everything is in a known state */
  Serial.println(F("Performing a factory reset: "));

  if ( ! ble.factoryReset() ){
    Serial.println(F("Couldn't factory reset"));
  }

  /* Disable command echo from Bluefruit */
  ble.echo(false);

  Serial.println("Requesting Bluefruit info:");

  /* Print Bluefruit information */
  ble.info();

  // debug info is a little annoying after this point!
  ble.verbose(false);

  // Set device name
  Serial.println("Set Device Name to Blue Car");
  ble.sendCommandCheckOK("AT+GAPDEVNAME=Blue Car");

  Serial.println("Set Up Pins and Update Connections");

  setupPins();
  updateConnections();

  /* Wait for connection */
  Serial.println("Waiting For Connection");
  while (! ble.isConnected()) {
      digitalWrite(LED, HIGH);
      delay(250);
      digitalWrite(LED, LOW);
      delay(250);
  }

  Serial.println(F("******************************"));
  // Change Mode LED Activity
  Serial.println(F("Change LED activity to " MODE_LED_BEHAVIOUR));
  ble.sendCommandCheckOK("AT+HWModeLED=" MODE_LED_BEHAVIOUR);

  // Set module to DATA mode
  Serial.println( F("Switching to DATA mode!") );
  ble.setMode(BLUEFRUIT_MODE_DATA);

  Serial.println(F("******************************"));
}

//
// Setup Pins
//
void setupPins(){
    for (int i = 0; i < NUM_I_PINS; i++){
        pinMode(iPins[i], INPUT_PULLUP);
    }

    for (int i = 0; i < NUM_O_PINS; i++){
        pinMode(oPins[i], OUTPUT);
    }
}

void loop(){
  // Check for input from serial port
  char n, inputs[BUFSIZE+1];

  if (Serial.available()){
    n = Serial.readBytes(inputs, BUFSIZE);
    inputs[n] = 0;
    // Send characters to Bluefruit
    Serial.print("Sending: ");
    Serial.print(inputs);

    // Send input data to host via Bluefruit
    ble.write(inputs);
  }

  // Echo received data
  while (ble.available()){
      processMessage();
  }


}

//
// Checks who is connected
//
void updateConnections(){
    bool didUpdate = false;

    //first get pin states
    for (int i = 0; i < NUM_I_PINS; i++){
        if (digitalRead(iPins[i]) != HIGH){
            if (pinState[i] != LOW){
                didUpdate = true;
                pinState[i] = HIGH;

                //update module info
                if (i%2 == 0){
                    modules[i/2] = module{NULL, NULL, NULL, i, i+1, i+2};

                    Serial.println("Requesting data from nano");

                    modules[i/2].id = SPI.transfer(0x01);
                    Serial.println(modules[i/2].id);
                    modules[i/2].hardwareVersion = SPI.transfer(0x02);
                    modules[i/2].softwareVersion = SPI.transfer(0x03);

                }

            }
        } else {
            if (pinState[i] != HIGH){
                didUpdate = true;

                pinState[i] = LOW;
            }
        }
    }

    //update number of connected modules
    if (didUpdate){
        numConnectedModules = 0;

        for (int i = 0; i < NUM_I_PINS; i+=2){
            if (pinState[i] = LOW){
                numConnectedModules++;
            }
        }

        Serial.println("----------- Did Update Connections -----------");
        Serial.print("Number of connected modules: ");
        Serial.println(numConnectedModules);
    }

}

//
// Handles a message
//
void processMessage(){
    byte c = ble.read();

    Serial.print("MessageID: ");
    Serial.println(c, HEX);
}

FYI, this is public :)