Zoltan Hudak / Mbed 2 deprecated BLE_nRF24L01

Bluetooth Low Energy (BLE) beacon with nRF24L01(+). Data is received and displayed by Android device (Android app source code is attached).

Dependencies:   DS1820 mbed

nRF24L01 as Bluetooth Low Energy (BLE) Broadcaster/Beacon

Temperature measured by a DS1820 sensor is broadcasted by a nRF24L01(+) module as Bluetooth Low Energy signal. Data is then received and displayed on an Android device (smartphone/tablet) with Bluetooth Low Energy (Bluetooth Smart) enabled. In order to have Bluetooth LE available your device should run Android 4.3 or more recent.

Needed parts:

Zoom in /media/uploads/hudakz/img_20150314_115402.jpg
Figure 1: The hookup and the Android app in action

It was Dmitry Grinberg who figured out how to use nRF24L01 for BLE.
Read his amazing "Bit-banging" Bluetooth Low Energy. Thank you Dmitry!
I ported the code to mbed from Lijun's repository. Read his very neat article on the topic. Thank you Lijun!

It takes just few steps to build a Temperature Beacon

  1. Connect the nRF24L01(+) module and the DS1820 sensor to the mbed board according to the pin assignment defined in main.cpp. Don't forget to connect a 4.7k Ohm resistor between the DS1820's data pin and the +3.3V pin.

    /media/uploads/hudakz/nrf24l01.png
    Figure 2: nRF24L01(+) pinout

  2. Compile the project and save the binary file to your mbed module.
  3. Enable Bluetooth on the Android device.
  4. To view the raw data, install Nordic's nRF Master Control Panel (available at Google Play for free) to your Android device. Run the app and wait until a new nRF24L01 device is found. Do not tap the CONNECT button. This device is a broadcaster and enables only one way data flow (from the mbed to the Android). To see more details, tap the found nRF24L01 device on the left side of the screen and then the small RAW button which appears on the right side just below the CONNECT button. Now you should be able to see and check the raw bytes received from the mbed.
  5. Install the Android app:
    - Download the TemperatureBeacon app to your computer's folder of choice.
    - Open the folder and copy (send via Bluetooth or USB cable) the downloaded file to your Android device.
    - To install the app, open the folder on the Android with the file downloaded in the previous step and tap it.
  6. Once the app is installed and running:
    - After a while you should see the temperature displayed on Android (See in Figure 1).
    - Data is periodically updated. To verify that, touch the DS1820 sensor and you should see some new values.

If you'd like to adapt the Android app to your taste

  • Install Android Studio onto your computer (Window, Mac, Linux). It's a fantastic IDE from Google for free.
  • Download the Android app project to your computer's folder of choice and unzip.
  • Start Android Studio, open the project downloaded in the previous step and have fun.

I have learnt a lot about Android and Bluetooth Low Energy here:
https://developer.android.com/guide/topics/connectivity/bluetooth-le.html,
https://thenewcircle.com/s/post/1553/bluetooth_smart_le_android_tutorial

The Android app is based on:
https://github.com/devunwired/accessory-samples/tree/master/BluetoothGatt.
Thank you Dave!

main.cpp@1:ef3cc9be1f60, 2015-03-14 (annotated)

Committer:
hudakz
Date:
Sat Mar 14 13:12:40 2015 +0000
Revision:
1:ef3cc9be1f60
Parent:
0:6f3139e3410e
Child:
2:4f285d1d5c1f
nRF24L01+ as a Bluetooth Low Energy Broadcaster/Beacon by hacking nRF24L01+ module (which is under $1 per unit on eBay

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 0:6f3139e3410e 1 /*
hudakz 0:6f3139e3410e 2 nRF24L01+ as a Bluetooth Low Energy Broadcaster/Beacon
hudakz 0:6f3139e3410e 3 by hacking an nRF24L01+ module (which is under $1 per unit on eBay).
hudakz 0:6f3139e3410e 4
hudakz 0:6f3139e3410e 5 Note: It works also with the older nRF24L01 modules (without the +).
hudakz 0:6f3139e3410e 6
hudakz 1:ef3cc9be1f60 7 In this project we broadcast temperature readings measured by a DS1820 chip.
hudakz 0:6f3139e3410e 8 (You can easily modify the code to broadcast some other custom data.
hudakz 0:6f3139e3410e 9 Only make sure not to exceed the 32 bytes packet length.)
hudakz 0:6f3139e3410e 10
hudakz 0:6f3139e3410e 11 */
hudakz 0:6f3139e3410e 12
hudakz 0:6f3139e3410e 13
hudakz 0:6f3139e3410e 14 #include "mbed.h"
hudakz 0:6f3139e3410e 15 #include "DS1820.h"
hudakz 0:6f3139e3410e 16
hudakz 0:6f3139e3410e 17 Serial serial(USBTX, USBRX);
hudakz 0:6f3139e3410e 18
hudakz 0:6f3139e3410e 19 // The MAC address of BLE advertizer -- just make one up
hudakz 0:6f3139e3410e 20 // If you decide to ceate more Beacons make sure that MAC address (MY_MAC) is unique (differs)
hudakz 0:6f3139e3410e 21
hudakz 0:6f3139e3410e 22 #define MY_MAC_0 0x11
hudakz 0:6f3139e3410e 23 #define MY_MAC_1 0x12
hudakz 0:6f3139e3410e 24 #define MY_MAC_2 0x33
hudakz 0:6f3139e3410e 25 #define MY_MAC_3 0x44
hudakz 0:6f3139e3410e 26 #define MY_MAC_4 0x55
hudakz 0:6f3139e3410e 27 #define MY_MAC_5 0x66
hudakz 0:6f3139e3410e 28
hudakz 0:6f3139e3410e 29 #if defined(TARGET_LPC1768)
hudakz 0:6f3139e3410e 30 SPI spi(p11, p12, p13); // MOSI, MISO, SCK
hudakz 0:6f3139e3410e 31 DigitalOut cs(p8); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 32 DigitalOut ce(p14); // CE (enable nRF24L01+ chip)
hudakz 0:6f3139e3410e 33 DS1820 ds1820(p15);
hudakz 1:ef3cc9be1f60 34 #elif defined(TARGET_FRDM_KL25Z)
hudakz 1:ef3cc9be1f60 35 SPI spi(PTD2, PTD3, PTD1); // MOSI, MISO, SCK
hudakz 1:ef3cc9be1f60 36 DigitalOut cs(PTD0); // CSN (select SPI chip/slave)
hudakz 1:ef3cc9be1f60 37 DigitalOut ce(PTD5); // CE (enable nRF24L01+ chip)
hudakz 1:ef3cc9be1f60 38 DS1820 ds1820(PTA13);
hudakz 1:ef3cc9be1f60 39 #elif defined(TARGET_FRDM_KL46Z)
hudakz 1:ef3cc9be1f60 40 SPI spi(PTD2, PTD3, PTD1); // MOSI, MISO, SCK
hudakz 1:ef3cc9be1f60 41 DigitalOut cs(PTD0); // CSN (select SPI chip/slave)
hudakz 1:ef3cc9be1f60 42 DigitalOut ce(PTD5); // CE (enable nRF24L01+ chip)
hudakz 1:ef3cc9be1f60 43 DS1820 ds1820(PTA13);
hudakz 1:ef3cc9be1f60 44 #elif defined(TARGET_LPC11U24)
hudakz 1:ef3cc9be1f60 45 SPI spi(P16, P15, P13); // MOSI, MISO, SCK
hudakz 1:ef3cc9be1f60 46 DigitalOut cs(P17); // CSN (select SPI chip/slave)
hudakz 1:ef3cc9be1f60 47 DigitalOut ce(P18); // CE (enable nRF24L01+ chip)
hudakz 1:ef3cc9be1f60 48 DS1820 ds1820(P10);
hudakz 0:6f3139e3410e 49 #elif defined(TARGET_NUCLEO_F103RB)
hudakz 0:6f3139e3410e 50 SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz 0:6f3139e3410e 51 DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 52 DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz 0:6f3139e3410e 53 DS1820 ds1820(PA_9);
hudakz 0:6f3139e3410e 54 #elif defined(TARGET_NUCLEO_F401RE)
hudakz 0:6f3139e3410e 55 SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz 0:6f3139e3410e 56 DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 57 DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz 0:6f3139e3410e 58 DS1820 ds1820(PA_9);
hudakz 0:6f3139e3410e 59 #elif defined(TARGET_NUCLEO_F411RE)
hudakz 0:6f3139e3410e 60 SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz 0:6f3139e3410e 61 DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 62 DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz 0:6f3139e3410e 63 DS1820 ds1820(PA_9);
hudakz 0:6f3139e3410e 64
hudakz 0:6f3139e3410e 65 // If your board/plaform is not present yet then uncomment
hudakz 0:6f3139e3410e 66 // the following four lines and replace TARGET_YOUR_BOARD and CE_PIN as appropriate.
hudakz 0:6f3139e3410e 67
hudakz 0:6f3139e3410e 68 //#elif defined(TARGET_YOUR_BOARD)
hudakz 0:6f3139e3410e 69 //SPI spi(SPI_MOSI, SPI_MISO, SPI_SCK);
hudakz 0:6f3139e3410e 70 //DigitalOut cs(SPI_CS); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 71 //DigitalOut cs(CE_PIN); // CE (enable nRF24L01+ chip)
hudakz 0:6f3139e3410e 72 //DS1820 ds1820(DS1820_PIN);
hudakz 0:6f3139e3410e 73
hudakz 0:6f3139e3410e 74 #endif
hudakz 0:6f3139e3410e 75
hudakz 0:6f3139e3410e 76 uint8_t buf[32];
hudakz 0:6f3139e3410e 77
hudakz 0:6f3139e3410e 78 /**
hudakz 0:6f3139e3410e 79 * @brief
hudakz 0:6f3139e3410e 80 * @note
hudakz 0:6f3139e3410e 81 * @param
hudakz 0:6f3139e3410e 82 * @retval
hudakz 0:6f3139e3410e 83 */
hudakz 0:6f3139e3410e 84 void bleCRC(const uint8_t* data, uint8_t len, uint8_t* dst) {
hudakz 0:6f3139e3410e 85
hudakz 0:6f3139e3410e 86 // implementing CRC with LFSR
hudakz 0:6f3139e3410e 87 uint8_t v, t, d;
hudakz 0:6f3139e3410e 88
hudakz 0:6f3139e3410e 89 while(len--) {
hudakz 0:6f3139e3410e 90 d = *data++;
hudakz 0:6f3139e3410e 91 for(v = 0; v < 8; v++, d >>= 1) {
hudakz 0:6f3139e3410e 92 t = dst[0] >> 7;
hudakz 0:6f3139e3410e 93 dst[0] <<= 1;
hudakz 0:6f3139e3410e 94 if(dst[1] & 0x80)
hudakz 0:6f3139e3410e 95 dst[0] |= 1;
hudakz 0:6f3139e3410e 96 dst[1] <<= 1;
hudakz 0:6f3139e3410e 97 if(dst[2] & 0x80)
hudakz 0:6f3139e3410e 98 dst[1] |= 1;
hudakz 0:6f3139e3410e 99 dst[2] <<= 1;
hudakz 0:6f3139e3410e 100
hudakz 0:6f3139e3410e 101 if(t != (d & 1)) {
hudakz 0:6f3139e3410e 102 dst[2] ^= 0x5B;
hudakz 0:6f3139e3410e 103 dst[1] ^= 0x06;
hudakz 0:6f3139e3410e 104 }
hudakz 0:6f3139e3410e 105 }
hudakz 0:6f3139e3410e 106 }
hudakz 0:6f3139e3410e 107 }
hudakz 0:6f3139e3410e 108
hudakz 0:6f3139e3410e 109 /**
hudakz 0:6f3139e3410e 110 * @brief
hudakz 0:6f3139e3410e 111 * @note
hudakz 0:6f3139e3410e 112 * @param
hudakz 0:6f3139e3410e 113 * @retval
hudakz 0:6f3139e3410e 114 */
hudakz 0:6f3139e3410e 115 uint8_t swapBits(uint8_t a) {
hudakz 0:6f3139e3410e 116
hudakz 0:6f3139e3410e 117 // reverse the bit order in a single byte
hudakz 0:6f3139e3410e 118 uint8_t v = 0;
hudakz 0:6f3139e3410e 119 if(a & 0x80)
hudakz 0:6f3139e3410e 120 v |= 0x01;
hudakz 0:6f3139e3410e 121 if(a & 0x40)
hudakz 0:6f3139e3410e 122 v |= 0x02;
hudakz 0:6f3139e3410e 123 if(a & 0x20)
hudakz 0:6f3139e3410e 124 v |= 0x04;
hudakz 0:6f3139e3410e 125 if(a & 0x10)
hudakz 0:6f3139e3410e 126 v |= 0x08;
hudakz 0:6f3139e3410e 127 if(a & 0x08)
hudakz 0:6f3139e3410e 128 v |= 0x10;
hudakz 0:6f3139e3410e 129 if(a & 0x04)
hudakz 0:6f3139e3410e 130 v |= 0x20;
hudakz 0:6f3139e3410e 131 if(a & 0x02)
hudakz 0:6f3139e3410e 132 v |= 0x40;
hudakz 0:6f3139e3410e 133 if(a & 0x01)
hudakz 0:6f3139e3410e 134 v |= 0x80;
hudakz 0:6f3139e3410e 135 return v;
hudakz 0:6f3139e3410e 136 }
hudakz 0:6f3139e3410e 137
hudakz 0:6f3139e3410e 138 /**
hudakz 0:6f3139e3410e 139 * @brief
hudakz 0:6f3139e3410e 140 * @note
hudakz 0:6f3139e3410e 141 * @param
hudakz 0:6f3139e3410e 142 * @retval
hudakz 0:6f3139e3410e 143 */
hudakz 0:6f3139e3410e 144 void bleWhiten(uint8_t* data, uint8_t len, uint8_t whitenCoeff) {
hudakz 0:6f3139e3410e 145
hudakz 0:6f3139e3410e 146 // Implementing whitening with LFSR
hudakz 0:6f3139e3410e 147 uint8_t m;
hudakz 0:6f3139e3410e 148 while(len--) {
hudakz 0:6f3139e3410e 149 for(m = 1; m; m <<= 1) {
hudakz 0:6f3139e3410e 150 if(whitenCoeff & 0x80) {
hudakz 0:6f3139e3410e 151 whitenCoeff ^= 0x11;
hudakz 0:6f3139e3410e 152 (*data) ^= m;
hudakz 0:6f3139e3410e 153 }
hudakz 0:6f3139e3410e 154
hudakz 0:6f3139e3410e 155 whitenCoeff <<= 1;
hudakz 0:6f3139e3410e 156 }
hudakz 0:6f3139e3410e 157
hudakz 0:6f3139e3410e 158 data++;
hudakz 0:6f3139e3410e 159 }
hudakz 0:6f3139e3410e 160 }
hudakz 0:6f3139e3410e 161
hudakz 0:6f3139e3410e 162 /**
hudakz 0:6f3139e3410e 163 * @brief
hudakz 0:6f3139e3410e 164 * @note
hudakz 0:6f3139e3410e 165 * @param
hudakz 0:6f3139e3410e 166 * @retval
hudakz 0:6f3139e3410e 167 */
hudakz 0:6f3139e3410e 168 static inline uint8_t bleWhitenStart(uint8_t chan) {
hudakz 0:6f3139e3410e 169
hudakz 0:6f3139e3410e 170 //the value we actually use is what BT'd use left shifted one...makes our life easier
hudakz 0:6f3139e3410e 171
hudakz 0:6f3139e3410e 172 return swapBits(chan) | 2;
hudakz 0:6f3139e3410e 173 }
hudakz 0:6f3139e3410e 174
hudakz 0:6f3139e3410e 175 /**
hudakz 0:6f3139e3410e 176 * @brief
hudakz 0:6f3139e3410e 177 * @note
hudakz 0:6f3139e3410e 178 * @param
hudakz 0:6f3139e3410e 179 * @retval
hudakz 0:6f3139e3410e 180 */
hudakz 0:6f3139e3410e 181 void blePacketEncode(uint8_t* packet, uint8_t len, uint8_t chan) {
hudakz 0:6f3139e3410e 182
hudakz 0:6f3139e3410e 183 // Assemble the packet to be transmitted
hudakz 0:6f3139e3410e 184
hudakz 0:6f3139e3410e 185 // Length is of packet, including crc. pre-populate crc in packet with initial crc value!
hudakz 0:6f3139e3410e 186 uint8_t i, dataLen = len - 3;
hudakz 0:6f3139e3410e 187 bleCRC(packet, dataLen, packet + dataLen);
hudakz 0:6f3139e3410e 188 for(i = 0; i < 3; i++, dataLen++)
hudakz 0:6f3139e3410e 189 packet[dataLen] = swapBits(packet[dataLen]);
hudakz 0:6f3139e3410e 190 bleWhiten(packet, len, bleWhitenStart(chan));
hudakz 0:6f3139e3410e 191 for(i = 0; i < len; i++)
hudakz 0:6f3139e3410e 192 packet[i] = swapBits(packet[i]); // the byte order of the packet should be reversed as well
hudakz 0:6f3139e3410e 193 }
hudakz 0:6f3139e3410e 194
hudakz 0:6f3139e3410e 195 /**
hudakz 0:6f3139e3410e 196 * @brief
hudakz 0:6f3139e3410e 197 * @note
hudakz 0:6f3139e3410e 198 * @param
hudakz 0:6f3139e3410e 199 * @retval
hudakz 0:6f3139e3410e 200 */
hudakz 0:6f3139e3410e 201 void nrfCmd(uint8_t cmd, uint8_t data) {
hudakz 0:6f3139e3410e 202
hudakz 0:6f3139e3410e 203 // Write to nRF24's register
hudakz 0:6f3139e3410e 204
hudakz 0:6f3139e3410e 205 cs = 0;
hudakz 0:6f3139e3410e 206 spi.write(cmd);
hudakz 0:6f3139e3410e 207 spi.write(data);
hudakz 0:6f3139e3410e 208 cs = 1;
hudakz 0:6f3139e3410e 209 }
hudakz 0:6f3139e3410e 210
hudakz 0:6f3139e3410e 211 /**
hudakz 0:6f3139e3410e 212 * @brief
hudakz 0:6f3139e3410e 213 * @note
hudakz 0:6f3139e3410e 214 * @param
hudakz 0:6f3139e3410e 215 * @retval
hudakz 0:6f3139e3410e 216 */
hudakz 0:6f3139e3410e 217 void nrfWriteByte(uint8_t cmd) {
hudakz 0:6f3139e3410e 218 // transfer only one byte
hudakz 0:6f3139e3410e 219 cs = 0;
hudakz 0:6f3139e3410e 220 spi.write(cmd);
hudakz 0:6f3139e3410e 221 cs = 1;
hudakz 0:6f3139e3410e 222 }
hudakz 0:6f3139e3410e 223
hudakz 0:6f3139e3410e 224 /**
hudakz 0:6f3139e3410e 225 * @brief
hudakz 0:6f3139e3410e 226 * @note
hudakz 0:6f3139e3410e 227 * @param
hudakz 0:6f3139e3410e 228 * @retval
hudakz 0:6f3139e3410e 229 */
hudakz 0:6f3139e3410e 230 void nrfWriteBytes(uint8_t* data, uint8_t len) {
hudakz 0:6f3139e3410e 231 // transfer several bytes in a row
hudakz 0:6f3139e3410e 232 cs = 0;
hudakz 0:6f3139e3410e 233 do
hudakz 0:6f3139e3410e 234 {
hudakz 0:6f3139e3410e 235 spi.write(*data++);
hudakz 0:6f3139e3410e 236 } while(--len);
hudakz 0:6f3139e3410e 237 cs = 1;
hudakz 0:6f3139e3410e 238 }
hudakz 0:6f3139e3410e 239
hudakz 0:6f3139e3410e 240 int main() {
hudakz 0:6f3139e3410e 241 uint8_t data[4];
hudakz 0:6f3139e3410e 242 float* temp = reinterpret_cast < float * > (&data[0]);
hudakz 0:6f3139e3410e 243
hudakz 0:6f3139e3410e 244 // Chip must be deselected
hudakz 0:6f3139e3410e 245 cs = 1;
hudakz 0:6f3139e3410e 246
hudakz 0:6f3139e3410e 247 // Setup the spi for 8 bit data, high steady state clock,
hudakz 0:6f3139e3410e 248 // second edge capture, with a 10MHz clock rate
hudakz 0:6f3139e3410e 249 spi.format(8,0);
hudakz 0:6f3139e3410e 250 spi.frequency(10000000);
hudakz 0:6f3139e3410e 251
hudakz 0:6f3139e3410e 252 cs = 1;
hudakz 0:6f3139e3410e 253 ce = 0;
hudakz 0:6f3139e3410e 254
hudakz 0:6f3139e3410e 255 // Initialize nRF24L01+, setting general parameters
hudakz 0:6f3139e3410e 256 nrfCmd(0x20, 0x12); // on, no crc, int on RX/TX done
hudakz 0:6f3139e3410e 257 nrfCmd(0x21, 0x00); // no auto-acknowledge
hudakz 0:6f3139e3410e 258 nrfCmd(0x22, 0x00); // no RX
hudakz 0:6f3139e3410e 259 nrfCmd(0x23, 0x02); // 4-byte address
hudakz 0:6f3139e3410e 260 nrfCmd(0x24, 0x00); // no auto-retransmit
hudakz 0:6f3139e3410e 261 nrfCmd(0x26, 0x06); // 1MBps at 0dBm
hudakz 0:6f3139e3410e 262 nrfCmd(0x27, 0x3E); // clear various flags
hudakz 0:6f3139e3410e 263 nrfCmd(0x3C, 0x00); // no dynamic payloads
hudakz 0:6f3139e3410e 264 nrfCmd(0x3D, 0x00); // no features
hudakz 0:6f3139e3410e 265 nrfCmd(0x31, 32); // always RX 32 bytes
hudakz 0:6f3139e3410e 266 nrfCmd(0x22, 0x01); // RX on pipe 0
hudakz 0:6f3139e3410e 267
hudakz 0:6f3139e3410e 268 // Set access addresses (TX address in nRF24L01) to BLE advertising 0x8E89BED6
hudakz 0:6f3139e3410e 269 // Remember that both bit and byte orders are reversed for BLE packet format
hudakz 0:6f3139e3410e 270 buf[0] = 0x30;
hudakz 0:6f3139e3410e 271 buf[1] = swapBits(0x8E);
hudakz 0:6f3139e3410e 272 buf[2] = swapBits(0x89);
hudakz 0:6f3139e3410e 273 buf[3] = swapBits(0xBE);
hudakz 0:6f3139e3410e 274 buf[4] = swapBits(0xD6);
hudakz 0:6f3139e3410e 275 nrfWriteBytes(buf, 5);
hudakz 0:6f3139e3410e 276 buf[0] = 0x2A; // set RX address in nRF24L01, doesn't matter because RX is ignored in this case
hudakz 0:6f3139e3410e 277 nrfWriteBytes(buf, 5);
hudakz 0:6f3139e3410e 278 ds1820.begin();
hudakz 0:6f3139e3410e 279
hudakz 0:6f3139e3410e 280 while(1) {
hudakz 0:6f3139e3410e 281 static const uint8_t chRf[] = { 2, 26, 80 };
hudakz 0:6f3139e3410e 282 static const uint8_t chLe[] = { 37, 38, 39 };
hudakz 0:6f3139e3410e 283 uint8_t i = 0;
hudakz 0:6f3139e3410e 284 uint8_t j = 0;
hudakz 0:6f3139e3410e 285 uint8_t ch = 0;
hudakz 0:6f3139e3410e 286
hudakz 0:6f3139e3410e 287 *temp = ds1820.read();
hudakz 0:6f3139e3410e 288
hudakz 0:6f3139e3410e 289 // serial.printf("temp = %3.1f'C\r\n", *temp);
hudakz 0:6f3139e3410e 290
hudakz 0:6f3139e3410e 291 buf[i++] = 0x42; // PDU type, given address is random; 0x42 for Android and 0x40 for iPhone
hudakz 0:6f3139e3410e 292 buf[i++] = 25; // number of following data bytes, max 29 (CRC is not included)
hudakz 0:6f3139e3410e 293
hudakz 0:6f3139e3410e 294 //----------------------------
hudakz 0:6f3139e3410e 295 buf[i++] = MY_MAC_0;
hudakz 0:6f3139e3410e 296 buf[i++] = MY_MAC_1;
hudakz 0:6f3139e3410e 297 buf[i++] = MY_MAC_2;
hudakz 0:6f3139e3410e 298 buf[i++] = MY_MAC_3;
hudakz 0:6f3139e3410e 299 buf[i++] = MY_MAC_4;
hudakz 0:6f3139e3410e 300 buf[i++] = MY_MAC_5;
hudakz 0:6f3139e3410e 301
hudakz 0:6f3139e3410e 302 buf[i++] = 2; // flags (LE-only, limited discovery mode)
hudakz 0:6f3139e3410e 303 buf[i++] = 0x01;
hudakz 0:6f3139e3410e 304 buf[i++] = 0x05;
hudakz 0:6f3139e3410e 305
hudakz 0:6f3139e3410e 306 buf[i++] = 9; // length of the name, including type byte
hudakz 0:6f3139e3410e 307 buf[i++] = 0x08; // TYPE_NAME_SHORT
hudakz 0:6f3139e3410e 308 buf[i++] = 'n';
hudakz 0:6f3139e3410e 309 buf[i++] = 'R';
hudakz 0:6f3139e3410e 310 buf[i++] = 'F';
hudakz 0:6f3139e3410e 311 buf[i++] = '2';
hudakz 0:6f3139e3410e 312 buf[i++] = '4';
hudakz 0:6f3139e3410e 313 buf[i++] = 'L';
hudakz 0:6f3139e3410e 314 buf[i++] = '0';
hudakz 0:6f3139e3410e 315 buf[i++] = '1';
hudakz 0:6f3139e3410e 316
hudakz 0:6f3139e3410e 317 buf[i++] = 5; // length of custom data, including type byte
hudakz 0:6f3139e3410e 318 buf[i++] = 0xff; // TYPE_CUSTOMDATA
hudakz 0:6f3139e3410e 319
hudakz 0:6f3139e3410e 320 buf[i++] = data[0]; // temperature floating point value (four bytes)
hudakz 0:6f3139e3410e 321 buf[i++] = data[1];
hudakz 0:6f3139e3410e 322 buf[i++] = data[2];
hudakz 0:6f3139e3410e 323 buf[i++] = data[3];
hudakz 0:6f3139e3410e 324 //----------------------------
hudakz 0:6f3139e3410e 325
hudakz 0:6f3139e3410e 326 buf[i++] = 0x55; // CRC start value: 0x555555
hudakz 0:6f3139e3410e 327 buf[i++] = 0x55;
hudakz 0:6f3139e3410e 328 buf[i++] = 0x55;
hudakz 0:6f3139e3410e 329
hudakz 0:6f3139e3410e 330 // Channel hopping
hudakz 0:6f3139e3410e 331 if(++ch == sizeof(chRf))
hudakz 0:6f3139e3410e 332 ch = 0;
hudakz 0:6f3139e3410e 333 nrfCmd(0x25, chRf[ch]);
hudakz 0:6f3139e3410e 334 nrfCmd(0x27, 0x6E); // Clear flags
hudakz 0:6f3139e3410e 335 blePacketEncode(buf, i, chLe[ch]);
hudakz 0:6f3139e3410e 336 nrfWriteByte(0xE2); // Clear RX Fifo
hudakz 0:6f3139e3410e 337 nrfWriteByte(0xE1); // Clear TX Fifo
hudakz 0:6f3139e3410e 338 cs = 0;
hudakz 0:6f3139e3410e 339 spi.write(0xA0);
hudakz 0:6f3139e3410e 340 for(j = 0; j < i; j++)
hudakz 0:6f3139e3410e 341 spi.write(buf[j]);
hudakz 0:6f3139e3410e 342 cs = 1;
hudakz 0:6f3139e3410e 343
hudakz 0:6f3139e3410e 344 nrfCmd(0x20, 0x12); // TX on
hudakz 0:6f3139e3410e 345 ce = 1; // Enable Chip
hudakz 0:6f3139e3410e 346 wait_ms(50);
hudakz 0:6f3139e3410e 347 ce = 0; // (in preparation of switching to RX quickly)
hudakz 0:6f3139e3410e 348 ds1820.startConversion(); // Start temperature conversion
hudakz 0:6f3139e3410e 349 wait(1); // Broadcasting interval (change to your needs)
hudakz 0:6f3139e3410e 350 }
hudakz 0:6f3139e3410e 351 }