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@2:4f285d1d5c1f, 2015-03-14 (annotated)

Committer:
hudakz
Date:
Sat Mar 14 15:35:43 2015 +0000
Revision:
2:4f285d1d5c1f
Parent:
1:ef3cc9be1f60
Child:
3:96153a5d95f6
Debug option added

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 2:4f285d1d5c1f 10
hudakz 2:4f285d1d5c1f 11 The data can be received and displayed on an Android device (smartphone/tablet)
hudakz 2:4f285d1d5c1f 12 with Bluetooth Low Energy (Bluetooth Smart) enabled.
hudakz 2:4f285d1d5c1f 13 In order to have Bluetooth 4.0 available (which implements Bluetooth LE)
hudakz 2:4f285d1d5c1f 14 your device should run Android 4.3 or more recent.
hudakz 0:6f3139e3410e 15 */
hudakz 0:6f3139e3410e 16
hudakz 0:6f3139e3410e 17
hudakz 0:6f3139e3410e 18 #include "mbed.h"
hudakz 0:6f3139e3410e 19 #include "DS1820.h"
hudakz 0:6f3139e3410e 20
hudakz 2:4f285d1d5c1f 21 #define DEBUG 1
hudakz 2:4f285d1d5c1f 22
hudakz 2:4f285d1d5c1f 23 #if DEBUG
hudakz 0:6f3139e3410e 24 Serial serial(USBTX, USBRX);
hudakz 2:4f285d1d5c1f 25 #endif
hudakz 0:6f3139e3410e 26
hudakz 0:6f3139e3410e 27 // The MAC address of BLE advertizer -- just make one up
hudakz 0:6f3139e3410e 28 // If you decide to ceate more Beacons make sure that MAC address (MY_MAC) is unique (differs)
hudakz 0:6f3139e3410e 29
hudakz 0:6f3139e3410e 30 #define MY_MAC_0 0x11
hudakz 0:6f3139e3410e 31 #define MY_MAC_1 0x12
hudakz 0:6f3139e3410e 32 #define MY_MAC_2 0x33
hudakz 0:6f3139e3410e 33 #define MY_MAC_3 0x44
hudakz 0:6f3139e3410e 34 #define MY_MAC_4 0x55
hudakz 0:6f3139e3410e 35 #define MY_MAC_5 0x66
hudakz 0:6f3139e3410e 36
hudakz 0:6f3139e3410e 37 #if defined(TARGET_LPC1768)
hudakz 0:6f3139e3410e 38 SPI spi(p11, p12, p13); // MOSI, MISO, SCK
hudakz 0:6f3139e3410e 39 DigitalOut cs(p8); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 40 DigitalOut ce(p14); // CE (enable nRF24L01+ chip)
hudakz 0:6f3139e3410e 41 DS1820 ds1820(p15);
hudakz 1:ef3cc9be1f60 42 #elif defined(TARGET_FRDM_KL25Z)
hudakz 1:ef3cc9be1f60 43 SPI spi(PTD2, PTD3, PTD1); // MOSI, MISO, SCK
hudakz 1:ef3cc9be1f60 44 DigitalOut cs(PTD0); // CSN (select SPI chip/slave)
hudakz 1:ef3cc9be1f60 45 DigitalOut ce(PTD5); // CE (enable nRF24L01+ chip)
hudakz 1:ef3cc9be1f60 46 DS1820 ds1820(PTA13);
hudakz 1:ef3cc9be1f60 47 #elif defined(TARGET_FRDM_KL46Z)
hudakz 1:ef3cc9be1f60 48 SPI spi(PTD2, PTD3, PTD1); // MOSI, MISO, SCK
hudakz 1:ef3cc9be1f60 49 DigitalOut cs(PTD0); // CSN (select SPI chip/slave)
hudakz 1:ef3cc9be1f60 50 DigitalOut ce(PTD5); // CE (enable nRF24L01+ chip)
hudakz 1:ef3cc9be1f60 51 DS1820 ds1820(PTA13);
hudakz 1:ef3cc9be1f60 52 #elif defined(TARGET_LPC11U24)
hudakz 1:ef3cc9be1f60 53 SPI spi(P16, P15, P13); // MOSI, MISO, SCK
hudakz 1:ef3cc9be1f60 54 DigitalOut cs(P17); // CSN (select SPI chip/slave)
hudakz 1:ef3cc9be1f60 55 DigitalOut ce(P18); // CE (enable nRF24L01+ chip)
hudakz 1:ef3cc9be1f60 56 DS1820 ds1820(P10);
hudakz 0:6f3139e3410e 57 #elif defined(TARGET_NUCLEO_F103RB)
hudakz 0:6f3139e3410e 58 SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz 0:6f3139e3410e 59 DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 60 DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz 0:6f3139e3410e 61 DS1820 ds1820(PA_9);
hudakz 0:6f3139e3410e 62 #elif defined(TARGET_NUCLEO_F401RE)
hudakz 0:6f3139e3410e 63 SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz 0:6f3139e3410e 64 DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 65 DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz 0:6f3139e3410e 66 DS1820 ds1820(PA_9);
hudakz 0:6f3139e3410e 67 #elif defined(TARGET_NUCLEO_F411RE)
hudakz 0:6f3139e3410e 68 SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz 0:6f3139e3410e 69 DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 70 DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz 0:6f3139e3410e 71 DS1820 ds1820(PA_9);
hudakz 0:6f3139e3410e 72
hudakz 0:6f3139e3410e 73 // If your board/plaform is not present yet then uncomment
hudakz 0:6f3139e3410e 74 // the following four lines and replace TARGET_YOUR_BOARD and CE_PIN as appropriate.
hudakz 0:6f3139e3410e 75
hudakz 0:6f3139e3410e 76 //#elif defined(TARGET_YOUR_BOARD)
hudakz 0:6f3139e3410e 77 //SPI spi(SPI_MOSI, SPI_MISO, SPI_SCK);
hudakz 0:6f3139e3410e 78 //DigitalOut cs(SPI_CS); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 79 //DigitalOut cs(CE_PIN); // CE (enable nRF24L01+ chip)
hudakz 0:6f3139e3410e 80 //DS1820 ds1820(DS1820_PIN);
hudakz 0:6f3139e3410e 81
hudakz 0:6f3139e3410e 82 #endif
hudakz 0:6f3139e3410e 83
hudakz 0:6f3139e3410e 84 uint8_t buf[32];
hudakz 0:6f3139e3410e 85
hudakz 0:6f3139e3410e 86 /**
hudakz 0:6f3139e3410e 87 * @brief
hudakz 0:6f3139e3410e 88 * @note
hudakz 0:6f3139e3410e 89 * @param
hudakz 0:6f3139e3410e 90 * @retval
hudakz 0:6f3139e3410e 91 */
hudakz 0:6f3139e3410e 92 void bleCRC(const uint8_t* data, uint8_t len, uint8_t* dst) {
hudakz 0:6f3139e3410e 93
hudakz 0:6f3139e3410e 94 // implementing CRC with LFSR
hudakz 0:6f3139e3410e 95 uint8_t v, t, d;
hudakz 0:6f3139e3410e 96
hudakz 0:6f3139e3410e 97 while(len--) {
hudakz 0:6f3139e3410e 98 d = *data++;
hudakz 0:6f3139e3410e 99 for(v = 0; v < 8; v++, d >>= 1) {
hudakz 0:6f3139e3410e 100 t = dst[0] >> 7;
hudakz 0:6f3139e3410e 101 dst[0] <<= 1;
hudakz 0:6f3139e3410e 102 if(dst[1] & 0x80)
hudakz 0:6f3139e3410e 103 dst[0] |= 1;
hudakz 0:6f3139e3410e 104 dst[1] <<= 1;
hudakz 0:6f3139e3410e 105 if(dst[2] & 0x80)
hudakz 0:6f3139e3410e 106 dst[1] |= 1;
hudakz 0:6f3139e3410e 107 dst[2] <<= 1;
hudakz 0:6f3139e3410e 108
hudakz 0:6f3139e3410e 109 if(t != (d & 1)) {
hudakz 0:6f3139e3410e 110 dst[2] ^= 0x5B;
hudakz 0:6f3139e3410e 111 dst[1] ^= 0x06;
hudakz 0:6f3139e3410e 112 }
hudakz 0:6f3139e3410e 113 }
hudakz 0:6f3139e3410e 114 }
hudakz 0:6f3139e3410e 115 }
hudakz 0:6f3139e3410e 116
hudakz 0:6f3139e3410e 117 /**
hudakz 0:6f3139e3410e 118 * @brief
hudakz 0:6f3139e3410e 119 * @note
hudakz 0:6f3139e3410e 120 * @param
hudakz 0:6f3139e3410e 121 * @retval
hudakz 0:6f3139e3410e 122 */
hudakz 0:6f3139e3410e 123 uint8_t swapBits(uint8_t a) {
hudakz 0:6f3139e3410e 124
hudakz 0:6f3139e3410e 125 // reverse the bit order in a single byte
hudakz 0:6f3139e3410e 126 uint8_t v = 0;
hudakz 0:6f3139e3410e 127 if(a & 0x80)
hudakz 0:6f3139e3410e 128 v |= 0x01;
hudakz 0:6f3139e3410e 129 if(a & 0x40)
hudakz 0:6f3139e3410e 130 v |= 0x02;
hudakz 0:6f3139e3410e 131 if(a & 0x20)
hudakz 0:6f3139e3410e 132 v |= 0x04;
hudakz 0:6f3139e3410e 133 if(a & 0x10)
hudakz 0:6f3139e3410e 134 v |= 0x08;
hudakz 0:6f3139e3410e 135 if(a & 0x08)
hudakz 0:6f3139e3410e 136 v |= 0x10;
hudakz 0:6f3139e3410e 137 if(a & 0x04)
hudakz 0:6f3139e3410e 138 v |= 0x20;
hudakz 0:6f3139e3410e 139 if(a & 0x02)
hudakz 0:6f3139e3410e 140 v |= 0x40;
hudakz 0:6f3139e3410e 141 if(a & 0x01)
hudakz 0:6f3139e3410e 142 v |= 0x80;
hudakz 0:6f3139e3410e 143 return v;
hudakz 0:6f3139e3410e 144 }
hudakz 0:6f3139e3410e 145
hudakz 0:6f3139e3410e 146 /**
hudakz 0:6f3139e3410e 147 * @brief
hudakz 0:6f3139e3410e 148 * @note
hudakz 0:6f3139e3410e 149 * @param
hudakz 0:6f3139e3410e 150 * @retval
hudakz 0:6f3139e3410e 151 */
hudakz 0:6f3139e3410e 152 void bleWhiten(uint8_t* data, uint8_t len, uint8_t whitenCoeff) {
hudakz 0:6f3139e3410e 153
hudakz 0:6f3139e3410e 154 // Implementing whitening with LFSR
hudakz 0:6f3139e3410e 155 uint8_t m;
hudakz 0:6f3139e3410e 156 while(len--) {
hudakz 0:6f3139e3410e 157 for(m = 1; m; m <<= 1) {
hudakz 0:6f3139e3410e 158 if(whitenCoeff & 0x80) {
hudakz 0:6f3139e3410e 159 whitenCoeff ^= 0x11;
hudakz 0:6f3139e3410e 160 (*data) ^= m;
hudakz 0:6f3139e3410e 161 }
hudakz 0:6f3139e3410e 162
hudakz 0:6f3139e3410e 163 whitenCoeff <<= 1;
hudakz 0:6f3139e3410e 164 }
hudakz 0:6f3139e3410e 165
hudakz 0:6f3139e3410e 166 data++;
hudakz 0:6f3139e3410e 167 }
hudakz 0:6f3139e3410e 168 }
hudakz 0:6f3139e3410e 169
hudakz 0:6f3139e3410e 170 /**
hudakz 0:6f3139e3410e 171 * @brief
hudakz 0:6f3139e3410e 172 * @note
hudakz 0:6f3139e3410e 173 * @param
hudakz 0:6f3139e3410e 174 * @retval
hudakz 0:6f3139e3410e 175 */
hudakz 0:6f3139e3410e 176 static inline uint8_t bleWhitenStart(uint8_t chan) {
hudakz 0:6f3139e3410e 177
hudakz 0:6f3139e3410e 178 //the value we actually use is what BT'd use left shifted one...makes our life easier
hudakz 0:6f3139e3410e 179
hudakz 0:6f3139e3410e 180 return swapBits(chan) | 2;
hudakz 0:6f3139e3410e 181 }
hudakz 0:6f3139e3410e 182
hudakz 0:6f3139e3410e 183 /**
hudakz 0:6f3139e3410e 184 * @brief
hudakz 0:6f3139e3410e 185 * @note
hudakz 0:6f3139e3410e 186 * @param
hudakz 0:6f3139e3410e 187 * @retval
hudakz 0:6f3139e3410e 188 */
hudakz 0:6f3139e3410e 189 void blePacketEncode(uint8_t* packet, uint8_t len, uint8_t chan) {
hudakz 0:6f3139e3410e 190
hudakz 0:6f3139e3410e 191 // Assemble the packet to be transmitted
hudakz 0:6f3139e3410e 192
hudakz 0:6f3139e3410e 193 // Length is of packet, including crc. pre-populate crc in packet with initial crc value!
hudakz 0:6f3139e3410e 194 uint8_t i, dataLen = len - 3;
hudakz 0:6f3139e3410e 195 bleCRC(packet, dataLen, packet + dataLen);
hudakz 0:6f3139e3410e 196 for(i = 0; i < 3; i++, dataLen++)
hudakz 0:6f3139e3410e 197 packet[dataLen] = swapBits(packet[dataLen]);
hudakz 0:6f3139e3410e 198 bleWhiten(packet, len, bleWhitenStart(chan));
hudakz 0:6f3139e3410e 199 for(i = 0; i < len; i++)
hudakz 0:6f3139e3410e 200 packet[i] = swapBits(packet[i]); // the byte order of the packet should be reversed as well
hudakz 0:6f3139e3410e 201 }
hudakz 0:6f3139e3410e 202
hudakz 0:6f3139e3410e 203 /**
hudakz 0:6f3139e3410e 204 * @brief
hudakz 0:6f3139e3410e 205 * @note
hudakz 0:6f3139e3410e 206 * @param
hudakz 0:6f3139e3410e 207 * @retval
hudakz 0:6f3139e3410e 208 */
hudakz 0:6f3139e3410e 209 void nrfCmd(uint8_t cmd, uint8_t data) {
hudakz 0:6f3139e3410e 210
hudakz 0:6f3139e3410e 211 // Write to nRF24's register
hudakz 0:6f3139e3410e 212
hudakz 0:6f3139e3410e 213 cs = 0;
hudakz 0:6f3139e3410e 214 spi.write(cmd);
hudakz 0:6f3139e3410e 215 spi.write(data);
hudakz 0:6f3139e3410e 216 cs = 1;
hudakz 0:6f3139e3410e 217 }
hudakz 0:6f3139e3410e 218
hudakz 0:6f3139e3410e 219 /**
hudakz 0:6f3139e3410e 220 * @brief
hudakz 0:6f3139e3410e 221 * @note
hudakz 0:6f3139e3410e 222 * @param
hudakz 0:6f3139e3410e 223 * @retval
hudakz 0:6f3139e3410e 224 */
hudakz 0:6f3139e3410e 225 void nrfWriteByte(uint8_t cmd) {
hudakz 0:6f3139e3410e 226 // transfer only one byte
hudakz 0:6f3139e3410e 227 cs = 0;
hudakz 0:6f3139e3410e 228 spi.write(cmd);
hudakz 0:6f3139e3410e 229 cs = 1;
hudakz 0:6f3139e3410e 230 }
hudakz 0:6f3139e3410e 231
hudakz 0:6f3139e3410e 232 /**
hudakz 0:6f3139e3410e 233 * @brief
hudakz 0:6f3139e3410e 234 * @note
hudakz 0:6f3139e3410e 235 * @param
hudakz 0:6f3139e3410e 236 * @retval
hudakz 0:6f3139e3410e 237 */
hudakz 0:6f3139e3410e 238 void nrfWriteBytes(uint8_t* data, uint8_t len) {
hudakz 0:6f3139e3410e 239 // transfer several bytes in a row
hudakz 0:6f3139e3410e 240 cs = 0;
hudakz 0:6f3139e3410e 241 do
hudakz 0:6f3139e3410e 242 {
hudakz 0:6f3139e3410e 243 spi.write(*data++);
hudakz 0:6f3139e3410e 244 } while(--len);
hudakz 0:6f3139e3410e 245 cs = 1;
hudakz 0:6f3139e3410e 246 }
hudakz 0:6f3139e3410e 247
hudakz 0:6f3139e3410e 248 int main() {
hudakz 0:6f3139e3410e 249 uint8_t data[4];
hudakz 0:6f3139e3410e 250 float* temp = reinterpret_cast < float * > (&data[0]);
hudakz 0:6f3139e3410e 251
hudakz 0:6f3139e3410e 252 // Chip must be deselected
hudakz 0:6f3139e3410e 253 cs = 1;
hudakz 0:6f3139e3410e 254
hudakz 0:6f3139e3410e 255 // Setup the spi for 8 bit data, high steady state clock,
hudakz 0:6f3139e3410e 256 // second edge capture, with a 10MHz clock rate
hudakz 0:6f3139e3410e 257 spi.format(8,0);
hudakz 0:6f3139e3410e 258 spi.frequency(10000000);
hudakz 0:6f3139e3410e 259
hudakz 0:6f3139e3410e 260 cs = 1;
hudakz 0:6f3139e3410e 261 ce = 0;
hudakz 0:6f3139e3410e 262
hudakz 0:6f3139e3410e 263 // Initialize nRF24L01+, setting general parameters
hudakz 0:6f3139e3410e 264 nrfCmd(0x20, 0x12); // on, no crc, int on RX/TX done
hudakz 0:6f3139e3410e 265 nrfCmd(0x21, 0x00); // no auto-acknowledge
hudakz 0:6f3139e3410e 266 nrfCmd(0x22, 0x00); // no RX
hudakz 0:6f3139e3410e 267 nrfCmd(0x23, 0x02); // 4-byte address
hudakz 0:6f3139e3410e 268 nrfCmd(0x24, 0x00); // no auto-retransmit
hudakz 0:6f3139e3410e 269 nrfCmd(0x26, 0x06); // 1MBps at 0dBm
hudakz 0:6f3139e3410e 270 nrfCmd(0x27, 0x3E); // clear various flags
hudakz 0:6f3139e3410e 271 nrfCmd(0x3C, 0x00); // no dynamic payloads
hudakz 0:6f3139e3410e 272 nrfCmd(0x3D, 0x00); // no features
hudakz 0:6f3139e3410e 273 nrfCmd(0x31, 32); // always RX 32 bytes
hudakz 0:6f3139e3410e 274 nrfCmd(0x22, 0x01); // RX on pipe 0
hudakz 0:6f3139e3410e 275
hudakz 0:6f3139e3410e 276 // Set access addresses (TX address in nRF24L01) to BLE advertising 0x8E89BED6
hudakz 0:6f3139e3410e 277 // Remember that both bit and byte orders are reversed for BLE packet format
hudakz 0:6f3139e3410e 278 buf[0] = 0x30;
hudakz 0:6f3139e3410e 279 buf[1] = swapBits(0x8E);
hudakz 0:6f3139e3410e 280 buf[2] = swapBits(0x89);
hudakz 0:6f3139e3410e 281 buf[3] = swapBits(0xBE);
hudakz 0:6f3139e3410e 282 buf[4] = swapBits(0xD6);
hudakz 0:6f3139e3410e 283 nrfWriteBytes(buf, 5);
hudakz 0:6f3139e3410e 284 buf[0] = 0x2A; // set RX address in nRF24L01, doesn't matter because RX is ignored in this case
hudakz 0:6f3139e3410e 285 nrfWriteBytes(buf, 5);
hudakz 0:6f3139e3410e 286 ds1820.begin();
hudakz 0:6f3139e3410e 287
hudakz 0:6f3139e3410e 288 while(1) {
hudakz 0:6f3139e3410e 289 static const uint8_t chRf[] = { 2, 26, 80 };
hudakz 0:6f3139e3410e 290 static const uint8_t chLe[] = { 37, 38, 39 };
hudakz 0:6f3139e3410e 291 uint8_t i = 0;
hudakz 0:6f3139e3410e 292 uint8_t j = 0;
hudakz 0:6f3139e3410e 293 uint8_t ch = 0;
hudakz 0:6f3139e3410e 294
hudakz 0:6f3139e3410e 295 *temp = ds1820.read();
hudakz 2:4f285d1d5c1f 296
hudakz 2:4f285d1d5c1f 297 #if DEBUG
hudakz 2:4f285d1d5c1f 298 serial.printf("temp = %3.1f'C\r\n", *temp);
hudakz 2:4f285d1d5c1f 299 #endif
hudakz 0:6f3139e3410e 300
hudakz 0:6f3139e3410e 301 buf[i++] = 0x42; // PDU type, given address is random; 0x42 for Android and 0x40 for iPhone
hudakz 0:6f3139e3410e 302 buf[i++] = 25; // number of following data bytes, max 29 (CRC is not included)
hudakz 0:6f3139e3410e 303
hudakz 0:6f3139e3410e 304 //----------------------------
hudakz 0:6f3139e3410e 305 buf[i++] = MY_MAC_0;
hudakz 0:6f3139e3410e 306 buf[i++] = MY_MAC_1;
hudakz 0:6f3139e3410e 307 buf[i++] = MY_MAC_2;
hudakz 0:6f3139e3410e 308 buf[i++] = MY_MAC_3;
hudakz 0:6f3139e3410e 309 buf[i++] = MY_MAC_4;
hudakz 0:6f3139e3410e 310 buf[i++] = MY_MAC_5;
hudakz 0:6f3139e3410e 311
hudakz 0:6f3139e3410e 312 buf[i++] = 2; // flags (LE-only, limited discovery mode)
hudakz 0:6f3139e3410e 313 buf[i++] = 0x01;
hudakz 0:6f3139e3410e 314 buf[i++] = 0x05;
hudakz 0:6f3139e3410e 315
hudakz 0:6f3139e3410e 316 buf[i++] = 9; // length of the name, including type byte
hudakz 0:6f3139e3410e 317 buf[i++] = 0x08; // TYPE_NAME_SHORT
hudakz 0:6f3139e3410e 318 buf[i++] = 'n';
hudakz 0:6f3139e3410e 319 buf[i++] = 'R';
hudakz 0:6f3139e3410e 320 buf[i++] = 'F';
hudakz 0:6f3139e3410e 321 buf[i++] = '2';
hudakz 0:6f3139e3410e 322 buf[i++] = '4';
hudakz 0:6f3139e3410e 323 buf[i++] = 'L';
hudakz 0:6f3139e3410e 324 buf[i++] = '0';
hudakz 0:6f3139e3410e 325 buf[i++] = '1';
hudakz 0:6f3139e3410e 326
hudakz 0:6f3139e3410e 327 buf[i++] = 5; // length of custom data, including type byte
hudakz 0:6f3139e3410e 328 buf[i++] = 0xff; // TYPE_CUSTOMDATA
hudakz 0:6f3139e3410e 329
hudakz 0:6f3139e3410e 330 buf[i++] = data[0]; // temperature floating point value (four bytes)
hudakz 0:6f3139e3410e 331 buf[i++] = data[1];
hudakz 0:6f3139e3410e 332 buf[i++] = data[2];
hudakz 0:6f3139e3410e 333 buf[i++] = data[3];
hudakz 0:6f3139e3410e 334 //----------------------------
hudakz 0:6f3139e3410e 335
hudakz 0:6f3139e3410e 336 buf[i++] = 0x55; // CRC start value: 0x555555
hudakz 0:6f3139e3410e 337 buf[i++] = 0x55;
hudakz 0:6f3139e3410e 338 buf[i++] = 0x55;
hudakz 0:6f3139e3410e 339
hudakz 0:6f3139e3410e 340 // Channel hopping
hudakz 0:6f3139e3410e 341 if(++ch == sizeof(chRf))
hudakz 0:6f3139e3410e 342 ch = 0;
hudakz 0:6f3139e3410e 343 nrfCmd(0x25, chRf[ch]);
hudakz 0:6f3139e3410e 344 nrfCmd(0x27, 0x6E); // Clear flags
hudakz 0:6f3139e3410e 345 blePacketEncode(buf, i, chLe[ch]);
hudakz 0:6f3139e3410e 346 nrfWriteByte(0xE2); // Clear RX Fifo
hudakz 0:6f3139e3410e 347 nrfWriteByte(0xE1); // Clear TX Fifo
hudakz 2:4f285d1d5c1f 348
hudakz 0:6f3139e3410e 349 cs = 0;
hudakz 0:6f3139e3410e 350 spi.write(0xA0);
hudakz 0:6f3139e3410e 351 for(j = 0; j < i; j++)
hudakz 0:6f3139e3410e 352 spi.write(buf[j]);
hudakz 0:6f3139e3410e 353 cs = 1;
hudakz 0:6f3139e3410e 354
hudakz 0:6f3139e3410e 355 nrfCmd(0x20, 0x12); // TX on
hudakz 0:6f3139e3410e 356 ce = 1; // Enable Chip
hudakz 0:6f3139e3410e 357 wait_ms(50);
hudakz 0:6f3139e3410e 358 ce = 0; // (in preparation of switching to RX quickly)
hudakz 0:6f3139e3410e 359 ds1820.startConversion(); // Start temperature conversion
hudakz 0:6f3139e3410e 360 wait(1); // Broadcasting interval (change to your needs)
hudakz 0:6f3139e3410e 361 }
hudakz 0:6f3139e3410e 362 }