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@3:96153a5d95f6, 2015-03-15 (annotated)

Committer:
hudakz
Date:
Sun Mar 15 14:47:45 2015 +0000
Revision:
3:96153a5d95f6
Parent:
2:4f285d1d5c1f
Child:
4:b3c5c54cfd21
Support for additional boards added.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 0:6f3139e3410e 1 /*
hudakz 3:96153a5d95f6 2 Using nRF24L01(+) as a Bluetooth Low Energy Advertiser/Broadcaster/Beacon
hudakz 3:96153a5d95f6 3 by hacking an nRF24L01(+) module (which is under $1 per unit on eBay).
hudakz 0:6f3139e3410e 4
hudakz 3:96153a5d95f6 5 Note: It works with both nRF24L01 and nRF24L01+ modules.
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 3:96153a5d95f6 41 DS1820 ds1820(p15); // creates a ds1820 sensor
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 3:96153a5d95f6 46 DS1820 ds1820(PTA13); // creates a ds1820 sensor
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 3:96153a5d95f6 51 DS1820 ds1820(PTA13); // creates a ds1820 sensor
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 3:96153a5d95f6 56 DS1820 ds1820(P10); // creates a ds1820 sensor
hudakz 3:96153a5d95f6 57 #elif defined(TARGET_NUCLEO_F030R8)
hudakz 3:96153a5d95f6 58 SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz 3:96153a5d95f6 59 DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz 3:96153a5d95f6 60 DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz 3:96153a5d95f6 61 DS1820 ds1820(PA_9); // creates a ds1820 sensor
hudakz 3:96153a5d95f6 62 #elif defined(TARGET_NUCLEO_F072RB)
hudakz 3:96153a5d95f6 63 SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz 3:96153a5d95f6 64 DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz 3:96153a5d95f6 65 DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz 3:96153a5d95f6 66 DS1820 ds1820(PA_9); // creates a ds1820 sensor
hudakz 0:6f3139e3410e 67 #elif defined(TARGET_NUCLEO_F103RB)
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 3:96153a5d95f6 71 DS1820 ds1820(PA_9); // creates a ds1820 sensor
hudakz 0:6f3139e3410e 72 #elif defined(TARGET_NUCLEO_F401RE)
hudakz 0:6f3139e3410e 73 SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz 0:6f3139e3410e 74 DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 75 DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz 3:96153a5d95f6 76 DS1820 ds1820(PA_9); // creates a ds1820 sensor
hudakz 0:6f3139e3410e 77 #elif defined(TARGET_NUCLEO_F411RE)
hudakz 0:6f3139e3410e 78 SPI spi(PB_5, PB_4, PB_3); // MOSI, MISO, SCK
hudakz 0:6f3139e3410e 79 DigitalOut cs(PB_10); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 80 DigitalOut ce(PA_8); // CE (enable nRF24L01+ chip)
hudakz 3:96153a5d95f6 81 DS1820 ds1820(PA_9); // creates a ds1820 sensor
hudakz 0:6f3139e3410e 82
hudakz 0:6f3139e3410e 83 // If your board/plaform is not present yet then uncomment
hudakz 3:96153a5d95f6 84 // the following four lines and replace TARGET_YOUR_BOARD, SPI_MOSI, SPI_MISO, SPI_SCK, SPIS_CS, CE_PIN and DS1820_DATA_PIN as appropriate.
hudakz 0:6f3139e3410e 85
hudakz 0:6f3139e3410e 86 //#elif defined(TARGET_YOUR_BOARD)
hudakz 0:6f3139e3410e 87 //SPI spi(SPI_MOSI, SPI_MISO, SPI_SCK);
hudakz 0:6f3139e3410e 88 //DigitalOut cs(SPI_CS); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 89 //DigitalOut cs(CE_PIN); // CE (enable nRF24L01+ chip)
hudakz 3:96153a5d95f6 90 //DS1820 ds1820(DS1820_DATA_PIN);// creates a ds1820 sensor
hudakz 0:6f3139e3410e 91
hudakz 0:6f3139e3410e 92 #endif
hudakz 0:6f3139e3410e 93
hudakz 0:6f3139e3410e 94 uint8_t buf[32];
hudakz 0:6f3139e3410e 95
hudakz 0:6f3139e3410e 96 /**
hudakz 0:6f3139e3410e 97 * @brief
hudakz 0:6f3139e3410e 98 * @note
hudakz 0:6f3139e3410e 99 * @param
hudakz 0:6f3139e3410e 100 * @retval
hudakz 0:6f3139e3410e 101 */
hudakz 0:6f3139e3410e 102 void bleCRC(const uint8_t* data, uint8_t len, uint8_t* dst) {
hudakz 0:6f3139e3410e 103
hudakz 0:6f3139e3410e 104 // implementing CRC with LFSR
hudakz 0:6f3139e3410e 105 uint8_t v, t, d;
hudakz 0:6f3139e3410e 106
hudakz 0:6f3139e3410e 107 while(len--) {
hudakz 0:6f3139e3410e 108 d = *data++;
hudakz 0:6f3139e3410e 109 for(v = 0; v < 8; v++, d >>= 1) {
hudakz 0:6f3139e3410e 110 t = dst[0] >> 7;
hudakz 0:6f3139e3410e 111 dst[0] <<= 1;
hudakz 0:6f3139e3410e 112 if(dst[1] & 0x80)
hudakz 0:6f3139e3410e 113 dst[0] |= 1;
hudakz 0:6f3139e3410e 114 dst[1] <<= 1;
hudakz 0:6f3139e3410e 115 if(dst[2] & 0x80)
hudakz 0:6f3139e3410e 116 dst[1] |= 1;
hudakz 0:6f3139e3410e 117 dst[2] <<= 1;
hudakz 0:6f3139e3410e 118
hudakz 0:6f3139e3410e 119 if(t != (d & 1)) {
hudakz 0:6f3139e3410e 120 dst[2] ^= 0x5B;
hudakz 0:6f3139e3410e 121 dst[1] ^= 0x06;
hudakz 0:6f3139e3410e 122 }
hudakz 0:6f3139e3410e 123 }
hudakz 0:6f3139e3410e 124 }
hudakz 0:6f3139e3410e 125 }
hudakz 0:6f3139e3410e 126
hudakz 0:6f3139e3410e 127 /**
hudakz 0:6f3139e3410e 128 * @brief
hudakz 0:6f3139e3410e 129 * @note
hudakz 0:6f3139e3410e 130 * @param
hudakz 0:6f3139e3410e 131 * @retval
hudakz 0:6f3139e3410e 132 */
hudakz 0:6f3139e3410e 133 uint8_t swapBits(uint8_t a) {
hudakz 0:6f3139e3410e 134
hudakz 0:6f3139e3410e 135 // reverse the bit order in a single byte
hudakz 0:6f3139e3410e 136 uint8_t v = 0;
hudakz 0:6f3139e3410e 137 if(a & 0x80)
hudakz 0:6f3139e3410e 138 v |= 0x01;
hudakz 0:6f3139e3410e 139 if(a & 0x40)
hudakz 0:6f3139e3410e 140 v |= 0x02;
hudakz 0:6f3139e3410e 141 if(a & 0x20)
hudakz 0:6f3139e3410e 142 v |= 0x04;
hudakz 0:6f3139e3410e 143 if(a & 0x10)
hudakz 0:6f3139e3410e 144 v |= 0x08;
hudakz 0:6f3139e3410e 145 if(a & 0x08)
hudakz 0:6f3139e3410e 146 v |= 0x10;
hudakz 0:6f3139e3410e 147 if(a & 0x04)
hudakz 0:6f3139e3410e 148 v |= 0x20;
hudakz 0:6f3139e3410e 149 if(a & 0x02)
hudakz 0:6f3139e3410e 150 v |= 0x40;
hudakz 0:6f3139e3410e 151 if(a & 0x01)
hudakz 0:6f3139e3410e 152 v |= 0x80;
hudakz 0:6f3139e3410e 153 return v;
hudakz 0:6f3139e3410e 154 }
hudakz 0:6f3139e3410e 155
hudakz 0:6f3139e3410e 156 /**
hudakz 0:6f3139e3410e 157 * @brief
hudakz 0:6f3139e3410e 158 * @note
hudakz 0:6f3139e3410e 159 * @param
hudakz 0:6f3139e3410e 160 * @retval
hudakz 0:6f3139e3410e 161 */
hudakz 0:6f3139e3410e 162 void bleWhiten(uint8_t* data, uint8_t len, uint8_t whitenCoeff) {
hudakz 0:6f3139e3410e 163
hudakz 0:6f3139e3410e 164 // Implementing whitening with LFSR
hudakz 0:6f3139e3410e 165 uint8_t m;
hudakz 0:6f3139e3410e 166 while(len--) {
hudakz 0:6f3139e3410e 167 for(m = 1; m; m <<= 1) {
hudakz 0:6f3139e3410e 168 if(whitenCoeff & 0x80) {
hudakz 0:6f3139e3410e 169 whitenCoeff ^= 0x11;
hudakz 0:6f3139e3410e 170 (*data) ^= m;
hudakz 0:6f3139e3410e 171 }
hudakz 0:6f3139e3410e 172
hudakz 0:6f3139e3410e 173 whitenCoeff <<= 1;
hudakz 0:6f3139e3410e 174 }
hudakz 0:6f3139e3410e 175
hudakz 0:6f3139e3410e 176 data++;
hudakz 0:6f3139e3410e 177 }
hudakz 0:6f3139e3410e 178 }
hudakz 0:6f3139e3410e 179
hudakz 0:6f3139e3410e 180 /**
hudakz 0:6f3139e3410e 181 * @brief
hudakz 0:6f3139e3410e 182 * @note
hudakz 0:6f3139e3410e 183 * @param
hudakz 0:6f3139e3410e 184 * @retval
hudakz 0:6f3139e3410e 185 */
hudakz 0:6f3139e3410e 186 static inline uint8_t bleWhitenStart(uint8_t chan) {
hudakz 0:6f3139e3410e 187
hudakz 0:6f3139e3410e 188 //the value we actually use is what BT'd use left shifted one...makes our life easier
hudakz 0:6f3139e3410e 189
hudakz 0:6f3139e3410e 190 return swapBits(chan) | 2;
hudakz 0:6f3139e3410e 191 }
hudakz 0:6f3139e3410e 192
hudakz 0:6f3139e3410e 193 /**
hudakz 0:6f3139e3410e 194 * @brief
hudakz 0:6f3139e3410e 195 * @note
hudakz 0:6f3139e3410e 196 * @param
hudakz 0:6f3139e3410e 197 * @retval
hudakz 0:6f3139e3410e 198 */
hudakz 0:6f3139e3410e 199 void blePacketEncode(uint8_t* packet, uint8_t len, uint8_t chan) {
hudakz 0:6f3139e3410e 200
hudakz 0:6f3139e3410e 201 // Assemble the packet to be transmitted
hudakz 0:6f3139e3410e 202
hudakz 0:6f3139e3410e 203 // Length is of packet, including crc. pre-populate crc in packet with initial crc value!
hudakz 0:6f3139e3410e 204 uint8_t i, dataLen = len - 3;
hudakz 0:6f3139e3410e 205 bleCRC(packet, dataLen, packet + dataLen);
hudakz 0:6f3139e3410e 206 for(i = 0; i < 3; i++, dataLen++)
hudakz 0:6f3139e3410e 207 packet[dataLen] = swapBits(packet[dataLen]);
hudakz 0:6f3139e3410e 208 bleWhiten(packet, len, bleWhitenStart(chan));
hudakz 0:6f3139e3410e 209 for(i = 0; i < len; i++)
hudakz 0:6f3139e3410e 210 packet[i] = swapBits(packet[i]); // the byte order of the packet should be reversed as well
hudakz 0:6f3139e3410e 211 }
hudakz 0:6f3139e3410e 212
hudakz 0:6f3139e3410e 213 /**
hudakz 0:6f3139e3410e 214 * @brief
hudakz 0:6f3139e3410e 215 * @note
hudakz 0:6f3139e3410e 216 * @param
hudakz 0:6f3139e3410e 217 * @retval
hudakz 0:6f3139e3410e 218 */
hudakz 0:6f3139e3410e 219 void nrfCmd(uint8_t cmd, uint8_t data) {
hudakz 0:6f3139e3410e 220
hudakz 0:6f3139e3410e 221 // Write to nRF24's register
hudakz 0:6f3139e3410e 222
hudakz 0:6f3139e3410e 223 cs = 0;
hudakz 0:6f3139e3410e 224 spi.write(cmd);
hudakz 0:6f3139e3410e 225 spi.write(data);
hudakz 0:6f3139e3410e 226 cs = 1;
hudakz 0:6f3139e3410e 227 }
hudakz 0:6f3139e3410e 228
hudakz 0:6f3139e3410e 229 /**
hudakz 0:6f3139e3410e 230 * @brief
hudakz 0:6f3139e3410e 231 * @note
hudakz 0:6f3139e3410e 232 * @param
hudakz 0:6f3139e3410e 233 * @retval
hudakz 0:6f3139e3410e 234 */
hudakz 0:6f3139e3410e 235 void nrfWriteByte(uint8_t cmd) {
hudakz 0:6f3139e3410e 236 // transfer only one byte
hudakz 0:6f3139e3410e 237 cs = 0;
hudakz 0:6f3139e3410e 238 spi.write(cmd);
hudakz 0:6f3139e3410e 239 cs = 1;
hudakz 0:6f3139e3410e 240 }
hudakz 0:6f3139e3410e 241
hudakz 0:6f3139e3410e 242 /**
hudakz 0:6f3139e3410e 243 * @brief
hudakz 0:6f3139e3410e 244 * @note
hudakz 0:6f3139e3410e 245 * @param
hudakz 0:6f3139e3410e 246 * @retval
hudakz 0:6f3139e3410e 247 */
hudakz 0:6f3139e3410e 248 void nrfWriteBytes(uint8_t* data, uint8_t len) {
hudakz 0:6f3139e3410e 249 // transfer several bytes in a row
hudakz 0:6f3139e3410e 250 cs = 0;
hudakz 0:6f3139e3410e 251 do
hudakz 0:6f3139e3410e 252 {
hudakz 0:6f3139e3410e 253 spi.write(*data++);
hudakz 0:6f3139e3410e 254 } while(--len);
hudakz 0:6f3139e3410e 255 cs = 1;
hudakz 0:6f3139e3410e 256 }
hudakz 0:6f3139e3410e 257
hudakz 0:6f3139e3410e 258 int main() {
hudakz 0:6f3139e3410e 259 uint8_t data[4];
hudakz 0:6f3139e3410e 260 float* temp = reinterpret_cast < float * > (&data[0]);
hudakz 0:6f3139e3410e 261
hudakz 0:6f3139e3410e 262 // Chip must be deselected
hudakz 0:6f3139e3410e 263 cs = 1;
hudakz 0:6f3139e3410e 264
hudakz 0:6f3139e3410e 265 // Setup the spi for 8 bit data, high steady state clock,
hudakz 0:6f3139e3410e 266 // second edge capture, with a 10MHz clock rate
hudakz 0:6f3139e3410e 267 spi.format(8,0);
hudakz 0:6f3139e3410e 268 spi.frequency(10000000);
hudakz 0:6f3139e3410e 269
hudakz 0:6f3139e3410e 270 ce = 0;
hudakz 0:6f3139e3410e 271
hudakz 0:6f3139e3410e 272 // Initialize nRF24L01+, setting general parameters
hudakz 0:6f3139e3410e 273 nrfCmd(0x20, 0x12); // on, no crc, int on RX/TX done
hudakz 0:6f3139e3410e 274 nrfCmd(0x21, 0x00); // no auto-acknowledge
hudakz 0:6f3139e3410e 275 nrfCmd(0x22, 0x00); // no RX
hudakz 0:6f3139e3410e 276 nrfCmd(0x23, 0x02); // 4-byte address
hudakz 0:6f3139e3410e 277 nrfCmd(0x24, 0x00); // no auto-retransmit
hudakz 0:6f3139e3410e 278 nrfCmd(0x26, 0x06); // 1MBps at 0dBm
hudakz 0:6f3139e3410e 279 nrfCmd(0x27, 0x3E); // clear various flags
hudakz 0:6f3139e3410e 280 nrfCmd(0x3C, 0x00); // no dynamic payloads
hudakz 0:6f3139e3410e 281 nrfCmd(0x3D, 0x00); // no features
hudakz 0:6f3139e3410e 282 nrfCmd(0x31, 32); // always RX 32 bytes
hudakz 0:6f3139e3410e 283 nrfCmd(0x22, 0x01); // RX on pipe 0
hudakz 0:6f3139e3410e 284
hudakz 0:6f3139e3410e 285 // Set access addresses (TX address in nRF24L01) to BLE advertising 0x8E89BED6
hudakz 0:6f3139e3410e 286 // Remember that both bit and byte orders are reversed for BLE packet format
hudakz 0:6f3139e3410e 287 buf[0] = 0x30;
hudakz 0:6f3139e3410e 288 buf[1] = swapBits(0x8E);
hudakz 0:6f3139e3410e 289 buf[2] = swapBits(0x89);
hudakz 0:6f3139e3410e 290 buf[3] = swapBits(0xBE);
hudakz 0:6f3139e3410e 291 buf[4] = swapBits(0xD6);
hudakz 0:6f3139e3410e 292 nrfWriteBytes(buf, 5);
hudakz 0:6f3139e3410e 293 buf[0] = 0x2A; // set RX address in nRF24L01, doesn't matter because RX is ignored in this case
hudakz 0:6f3139e3410e 294 nrfWriteBytes(buf, 5);
hudakz 3:96153a5d95f6 295 if(!ds1820.begin()) {
hudakz 3:96153a5d95f6 296 #if DEBUG
hudakz 3:96153a5d95f6 297 serial.printf("No DS1820 sensor found!\r\n");
hudakz 3:96153a5d95f6 298 #endif
hudakz 3:96153a5d95f6 299 }
hudakz 3:96153a5d95f6 300
hudakz 0:6f3139e3410e 301
hudakz 0:6f3139e3410e 302 while(1) {
hudakz 0:6f3139e3410e 303 static const uint8_t chRf[] = { 2, 26, 80 };
hudakz 0:6f3139e3410e 304 static const uint8_t chLe[] = { 37, 38, 39 };
hudakz 0:6f3139e3410e 305 uint8_t i = 0;
hudakz 0:6f3139e3410e 306 uint8_t j = 0;
hudakz 0:6f3139e3410e 307 uint8_t ch = 0;
hudakz 0:6f3139e3410e 308
hudakz 0:6f3139e3410e 309 *temp = ds1820.read();
hudakz 2:4f285d1d5c1f 310
hudakz 2:4f285d1d5c1f 311 #if DEBUG
hudakz 2:4f285d1d5c1f 312 serial.printf("temp = %3.1f'C\r\n", *temp);
hudakz 2:4f285d1d5c1f 313 #endif
hudakz 0:6f3139e3410e 314
hudakz 0:6f3139e3410e 315 buf[i++] = 0x42; // PDU type, given address is random; 0x42 for Android and 0x40 for iPhone
hudakz 0:6f3139e3410e 316 buf[i++] = 25; // number of following data bytes, max 29 (CRC is not included)
hudakz 0:6f3139e3410e 317
hudakz 0:6f3139e3410e 318 //----------------------------
hudakz 0:6f3139e3410e 319 buf[i++] = MY_MAC_0;
hudakz 0:6f3139e3410e 320 buf[i++] = MY_MAC_1;
hudakz 0:6f3139e3410e 321 buf[i++] = MY_MAC_2;
hudakz 0:6f3139e3410e 322 buf[i++] = MY_MAC_3;
hudakz 0:6f3139e3410e 323 buf[i++] = MY_MAC_4;
hudakz 0:6f3139e3410e 324 buf[i++] = MY_MAC_5;
hudakz 0:6f3139e3410e 325
hudakz 0:6f3139e3410e 326 buf[i++] = 2; // flags (LE-only, limited discovery mode)
hudakz 0:6f3139e3410e 327 buf[i++] = 0x01;
hudakz 0:6f3139e3410e 328 buf[i++] = 0x05;
hudakz 0:6f3139e3410e 329
hudakz 0:6f3139e3410e 330 buf[i++] = 9; // length of the name, including type byte
hudakz 0:6f3139e3410e 331 buf[i++] = 0x08; // TYPE_NAME_SHORT
hudakz 0:6f3139e3410e 332 buf[i++] = 'n';
hudakz 0:6f3139e3410e 333 buf[i++] = 'R';
hudakz 0:6f3139e3410e 334 buf[i++] = 'F';
hudakz 0:6f3139e3410e 335 buf[i++] = '2';
hudakz 0:6f3139e3410e 336 buf[i++] = '4';
hudakz 0:6f3139e3410e 337 buf[i++] = 'L';
hudakz 0:6f3139e3410e 338 buf[i++] = '0';
hudakz 0:6f3139e3410e 339 buf[i++] = '1';
hudakz 0:6f3139e3410e 340
hudakz 0:6f3139e3410e 341 buf[i++] = 5; // length of custom data, including type byte
hudakz 0:6f3139e3410e 342 buf[i++] = 0xff; // TYPE_CUSTOMDATA
hudakz 0:6f3139e3410e 343
hudakz 0:6f3139e3410e 344 buf[i++] = data[0]; // temperature floating point value (four bytes)
hudakz 0:6f3139e3410e 345 buf[i++] = data[1];
hudakz 0:6f3139e3410e 346 buf[i++] = data[2];
hudakz 0:6f3139e3410e 347 buf[i++] = data[3];
hudakz 0:6f3139e3410e 348 //----------------------------
hudakz 0:6f3139e3410e 349
hudakz 0:6f3139e3410e 350 buf[i++] = 0x55; // CRC start value: 0x555555
hudakz 0:6f3139e3410e 351 buf[i++] = 0x55;
hudakz 0:6f3139e3410e 352 buf[i++] = 0x55;
hudakz 0:6f3139e3410e 353
hudakz 0:6f3139e3410e 354 // Channel hopping
hudakz 0:6f3139e3410e 355 if(++ch == sizeof(chRf))
hudakz 0:6f3139e3410e 356 ch = 0;
hudakz 0:6f3139e3410e 357 nrfCmd(0x25, chRf[ch]);
hudakz 0:6f3139e3410e 358 nrfCmd(0x27, 0x6E); // Clear flags
hudakz 0:6f3139e3410e 359 blePacketEncode(buf, i, chLe[ch]);
hudakz 0:6f3139e3410e 360 nrfWriteByte(0xE2); // Clear RX Fifo
hudakz 0:6f3139e3410e 361 nrfWriteByte(0xE1); // Clear TX Fifo
hudakz 2:4f285d1d5c1f 362
hudakz 0:6f3139e3410e 363 cs = 0;
hudakz 0:6f3139e3410e 364 spi.write(0xA0);
hudakz 0:6f3139e3410e 365 for(j = 0; j < i; j++)
hudakz 0:6f3139e3410e 366 spi.write(buf[j]);
hudakz 0:6f3139e3410e 367 cs = 1;
hudakz 0:6f3139e3410e 368
hudakz 0:6f3139e3410e 369 nrfCmd(0x20, 0x12); // TX on
hudakz 0:6f3139e3410e 370 ce = 1; // Enable Chip
hudakz 0:6f3139e3410e 371 wait_ms(50);
hudakz 0:6f3139e3410e 372 ce = 0; // (in preparation of switching to RX quickly)
hudakz 0:6f3139e3410e 373 ds1820.startConversion(); // Start temperature conversion
hudakz 3:96153a5d95f6 374 wait(1); // Broadcasting interval (shall be greater than ds1820 temperture converion time)
hudakz 0:6f3139e3410e 375 }
hudakz 0:6f3139e3410e 376 }