Another Ambassador Moment: Using the Adafruit Feather nRF52 Bluefruit LE

/*********************************************************************
 This is an example for our nRF52 based Bluefruit LE modules
 
 Pick one up today in the adafruit shop!
 
 Adafruit invests time and resources providing this open source code,
 please support Adafruit and open-source hardware by purchasing
 products from Adafruit!
 
 MIT license, check LICENSE for more information
 All text above, and the splash screen below must be included in
 any redistribution
*********************************************************************/
 
#include <bluefruit.h>
#include <Adafruit_NeoPixel.h>
 
// OTA DFU service
BLEDfu bledfu;
 
// Uart over BLE service
BLEUart bleuart;
 
// Function prototypes for packetparser.cpp
uint8_t readPacket (BLEUart *ble_uart, uint16_t timeout);
float   parsefloat (uint8_t *buffer);
void    printHex   (const uint8_t * data, const uint32_t numBytes);
 
// Packet buffer
extern uint8_t packetbuffer[];
 
 
Adafruit_NeoPixel pixel = Adafruit_NeoPixel(16, 5);
 
void setup(void)
{
  Serial.begin(115200);
  while ( !Serial ) delay(10);   // for nrf52840 with native usb
 
  // turn off neopixel
  pixel.begin(); // This initializes the NeoPixel library.
  for(uint8_t i=0; i<NUMPIXELS; i++) {
    pixel.setPixelColor(i, pixel.Color(0,0,0)); // off
  }
  pixel.show();
 
  Serial.println(F("Adafruit Bluefruit52 Controller App Example"));
  Serial.println(F("-------------------------------------------"));
 
  Bluefruit.begin();
  Bluefruit.setTxPower(4);    // Check bluefruit.h for supported values
  Bluefruit.setName("Bluefruit52");
 
  // To be consistent OTA DFU should be added first if it exists
  bledfu.begin();
 
  // Configure and start the BLE Uart service
  bleuart.begin();
 
  // Set up and start advertising
  startAdv();
 
  Serial.println(F("Please use Adafruit Bluefruit LE app to connect in Controller mode"));
  Serial.println(F("Then activate/use the sensors, color picker, game controller, etc!"));
  Serial.println();  
}
 
void startAdv(void)
{
  // Advertising packet
  Bluefruit.Advertising.addFlags(BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE);
  Bluefruit.Advertising.addTxPower();
  
  // Include the BLE UART (AKA 'NUS') 128-bit UUID
  Bluefruit.Advertising.addService(bleuart);
 
  // Secondary Scan Response packet (optional)
  // Since there is no room for 'Name' in Advertising packet
  Bluefruit.ScanResponse.addName();
 
  /* Start Advertising
   * - Enable auto advertising if disconnected
   * - Interval:  fast mode = 20 ms, slow mode = 152.5 ms
   * - Timeout for fast mode is 30 seconds
   * - Start(timeout) with timeout = 0 will advertise forever (until connected)
   * 
   * For recommended advertising interval
   * https://developer.apple.com/library/content/qa/qa1931/_index.html   
   */
  Bluefruit.Advertising.restartOnDisconnect(true);
  Bluefruit.Advertising.setInterval(32, 244);    // in unit of 0.625 ms
  Bluefruit.Advertising.setFastTimeout(30);      // number of seconds in fast mode
  Bluefruit.Advertising.start(0);                // 0 = Don't stop advertising after n seconds  
}
 
/**************************************************************************/
/*!
    @brief  Constantly poll for new command or response data
*/
/**************************************************************************/
void loop(void)
{
  // Wait for new data to arrive
  uint8_t len = readPacket(&bleuart, 500);
  if (len == 0) return;
 
  // Got a packet!
  // printHex(packetbuffer, len);
 
  // Color
  if (packetbuffer[1] == 'C') {
    uint8_t red = packetbuffer[2];
    uint8_t green = packetbuffer[3];
    uint8_t blue = packetbuffer[4];
    Serial.print ("RGB #");
    if (red < 0x10) Serial.print("0");
    Serial.print(red, HEX);
    if (green < 0x10) Serial.print("0");
    Serial.print(green, HEX);
    if (blue < 0x10) Serial.print("0");
    Serial.println(blue, HEX);
    for(uint8_t i=0; i<16; i++) {
      pixel.setPixelColor(i, pixel.Color(red,green,blue));
    }
    pixel.show(); // This sends the updated pixel color to the hardware.
  }
 
  // Buttons
  if (packetbuffer[1] == 'B') {
    uint8_t buttnum = packetbuffer[2] - '0';
    boolean pressed = packetbuffer[3] - '0';
    Serial.print ("Button "); Serial.print(buttnum);
    if (pressed) {
      Serial.println(" pressed");
    } else {
      Serial.println(" released");
    }
  }
 
  // GPS Location
  if (packetbuffer[1] == 'L') {
    float lat, lon, alt;
    lat = parsefloat(packetbuffer+2);
    lon = parsefloat(packetbuffer+6);
    alt = parsefloat(packetbuffer+10);
    Serial.print("GPS Location\t");
    Serial.print("Lat: "); Serial.print(lat, 4); // 4 digits of precision!
    Serial.print('\t');
    Serial.print("Lon: "); Serial.print(lon, 4); // 4 digits of precision!
    Serial.print('\t');
    Serial.print(alt, 4); Serial.println(" meters");
  }
 
  // Accelerometer
  if (packetbuffer[1] == 'A') {
    float x, y, z;
    x = parsefloat(packetbuffer+2);
    y = parsefloat(packetbuffer+6);
    z = parsefloat(packetbuffer+10);
    Serial.print("Accel\t");
    Serial.print(x); Serial.print('\t');
    Serial.print(y); Serial.print('\t');
    Serial.print(z); Serial.println();
  }
 
  // Magnetometer
  if (packetbuffer[1] == 'M') {
    float x, y, z;
    x = parsefloat(packetbuffer+2);
    y = parsefloat(packetbuffer+6);
    z = parsefloat(packetbuffer+10);
    Serial.print("Mag\t");
    Serial.print(x); Serial.print('\t');
    Serial.print(y); Serial.print('\t');
    Serial.print(z); Serial.println();
  }
 
  // Gyroscope
  if (packetbuffer[1] == 'G') {
    float x, y, z;
    x = parsefloat(packetbuffer+2);
    y = parsefloat(packetbuffer+6);
    z = parsefloat(packetbuffer+10);
    Serial.print("Gyro\t");
    Serial.print(x); Serial.print('\t');
    Serial.print(y); Serial.print('\t');
    Serial.print(z); Serial.println();
  }
 
  // Quaternions
  if (packetbuffer[1] == 'Q') {
    float x, y, z, w;
    x = parsefloat(packetbuffer+2);
    y = parsefloat(packetbuffer+6);
    z = parsefloat(packetbuffer+10);
    w = parsefloat(packetbuffer+14);
    Serial.print("Quat\t");
    Serial.print(x); Serial.print('\t');
    Serial.print(y); Serial.print('\t');
    Serial.print(z); Serial.print('\t');
    Serial.print(w); Serial.println();
  }
}

#include <string.h>
#include <Arduino.h>
#include <bluefruit.h>
 
 
#define PACKET_ACC_LEN                  (15)
#define PACKET_GYRO_LEN                 (15)
#define PACKET_MAG_LEN                  (15)
#define PACKET_QUAT_LEN                 (19)
#define PACKET_BUTTON_LEN               (5)
#define PACKET_COLOR_LEN                (6)
#define PACKET_LOCATION_LEN             (15)
 
//    READ_BUFSIZE            Size of the read buffer for incoming packets
#define READ_BUFSIZE                    (20)
 
 
/* Buffer to hold incoming characters */
uint8_t packetbuffer[READ_BUFSIZE+1];
 
/**************************************************************************/
/*!
    @brief  Casts the four bytes at the specified address to a float
*/
/**************************************************************************/
float parsefloat(uint8_t *buffer) 
{
  float f;
  memcpy(&f, buffer, 4);
  return f;
}
 
/**************************************************************************/
/*! 
    @brief  Prints a hexadecimal value in plain characters
    @param  data      Pointer to the byte data
    @param  numBytes  Data length in bytes
*/
/**************************************************************************/
void printHex(const uint8_t * data, const uint32_t numBytes)
{
  uint32_t szPos;
  for (szPos=0; szPos < numBytes; szPos++) 
  {
    Serial.print(F("0x"));
    // Append leading 0 for small values
    if (data[szPos] <= 0xF)
    {
      Serial.print(F("0"));
      Serial.print(data[szPos] & 0xf, HEX);
    }
    else
    {
      Serial.print(data[szPos] & 0xff, HEX);
    }
    // Add a trailing space if appropriate
    if ((numBytes > 1) && (szPos != numBytes - 1))
    {
      Serial.print(F(" "));
    }
  }
  Serial.println();
}
 
/**************************************************************************/
/*!
    @brief  Waits for incoming data and parses it
*/
/**************************************************************************/
uint8_t readPacket(BLEUart *ble_uart, uint16_t timeout) 
{
  uint16_t origtimeout = timeout, replyidx = 0;
 
  memset(packetbuffer, 0, READ_BUFSIZE);
 
  while (timeout--) {
    if (replyidx >= 20) break;
    if ((packetbuffer[1] == 'A') && (replyidx == PACKET_ACC_LEN))
      break;
    if ((packetbuffer[1] == 'G') && (replyidx == PACKET_GYRO_LEN))
      break;
    if ((packetbuffer[1] == 'M') && (replyidx == PACKET_MAG_LEN))
      break;
    if ((packetbuffer[1] == 'Q') && (replyidx == PACKET_QUAT_LEN))
      break;
    if ((packetbuffer[1] == 'B') && (replyidx == PACKET_BUTTON_LEN))
      break;
    if ((packetbuffer[1] == 'C') && (replyidx == PACKET_COLOR_LEN))
      break;
    if ((packetbuffer[1] == 'L') && (replyidx == PACKET_LOCATION_LEN))
      break;
 
    while (ble_uart->available()) {
      char c =  ble_uart->read();
      if (c == '!') {
        replyidx = 0;
      }
      packetbuffer[replyidx] = c;
      replyidx++;
      timeout = origtimeout;
    }
    
    if (timeout == 0) break;
    delay(1);
  }
 
  packetbuffer[replyidx] = 0;  // null term
 
  if (!replyidx)  // no data or timeout 
    return 0;
  if (packetbuffer[0] != '!')  // doesn't start with '!' packet beginning
    return 0;
  
  // check checksum!
  uint8_t xsum = 0;
  uint8_t checksum = packetbuffer[replyidx-1];
  
  for (uint8_t i=0; i<replyidx-1; i++) {
    xsum += packetbuffer[i];
  }
  xsum = ~xsum;
 
  // Throw an error message if the checksum's don't match
  if (xsum != checksum)
  {
    Serial.print("Checksum mismatch in packet : ");
    printHex(packetbuffer, replyidx+1);
    return 0;
  }
  
  // checksum passed!
  return replyidx;
}