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@7:79c3ff270db1, 2016-01-26 (annotated)

Committer:
hudakz
Date:
Tue Jan 26 23:16:31 2016 +0000
Revision:
7:79c3ff270db1
Parent:
6:14d70104b0fc 
Bug fixed.

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 6:14d70104b0fc 5 See wiki page: <https://developer.mbed.org/users/hudakz/code/BLE_nRF24L01>
hudakz 6:14d70104b0fc 6
hudakz 3:96153a5d95f6 7 Note: It works with both nRF24L01 and nRF24L01+ modules.
hudakz 0:6f3139e3410e 8
hudakz 6:14d70104b0fc 9 Temperature readings measured by a DS1820 chip are broacasted over Bluetooth LE.
hudakz 0:6f3139e3410e 10 (You can easily modify the code to broadcast some other custom data.
hudakz 0:6f3139e3410e 11 Only make sure not to exceed the 32 bytes packet length.)
hudakz 2:4f285d1d5c1f 12
hudakz 2:4f285d1d5c1f 13 The data can be received and displayed on an Android device (smartphone/tablet)
hudakz 2:4f285d1d5c1f 14 with Bluetooth Low Energy (Bluetooth Smart) enabled.
hudakz 2:4f285d1d5c1f 15 In order to have Bluetooth 4.0 available (which implements Bluetooth LE)
hudakz 2:4f285d1d5c1f 16 your device should run Android 4.3 or more recent.
hudakz 0:6f3139e3410e 17 */
hudakz 0:6f3139e3410e 18
hudakz 0:6f3139e3410e 19
hudakz 0:6f3139e3410e 20 #include "mbed.h"
hudakz 0:6f3139e3410e 21 #include "DS1820.h"
hudakz 0:6f3139e3410e 22
hudakz 2:4f285d1d5c1f 23 #define DEBUG 1
hudakz 2:4f285d1d5c1f 24
hudakz 2:4f285d1d5c1f 25 #if DEBUG
hudakz 0:6f3139e3410e 26 Serial serial(USBTX, USBRX);
hudakz 2:4f285d1d5c1f 27 #endif
hudakz 0:6f3139e3410e 28
hudakz 0:6f3139e3410e 29 // The MAC address of BLE advertizer -- just make one up
hudakz 6:14d70104b0fc 30 // If you decide to ceate more Beacons make sure that MAC address (MY_MAC) is unique for each beacon
hudakz 0:6f3139e3410e 31
hudakz 0:6f3139e3410e 32 #define MY_MAC_0 0x11
hudakz 0:6f3139e3410e 33 #define MY_MAC_1 0x12
hudakz 0:6f3139e3410e 34 #define MY_MAC_2 0x33
hudakz 0:6f3139e3410e 35 #define MY_MAC_3 0x44
hudakz 0:6f3139e3410e 36 #define MY_MAC_4 0x55
hudakz 0:6f3139e3410e 37 #define MY_MAC_5 0x66
hudakz 0:6f3139e3410e 38
hudakz 0:6f3139e3410e 39 #if defined(TARGET_LPC1768)
hudakz 0:6f3139e3410e 40 SPI spi(p11, p12, p13); // MOSI, MISO, SCK
hudakz 0:6f3139e3410e 41 DigitalOut cs(p8); // CSN (select SPI chip/slave)
hudakz 4:b3c5c54cfd21 42 DigitalOut ce(p14); // CE (enable nRF24L01 chip)
hudakz 4:b3c5c54cfd21 43 DS1820 ds1820(p15); // create a ds1820 sensor
hudakz 6:14d70104b0fc 44 #elif defined(TARGET_NUCLEO_F103RB) || defined(TARGET_NUCLEO_L152RE) || defined(TARGET_NUCLEO_F030R8) \
hudakz 6:14d70104b0fc 45 || defined(TARGET_NUCLEO_F401RE) || defined(TARGET_NUCLEO_F302R8) || defined(TARGET_NUCLEO_L053R8) \
hudakz 6:14d70104b0fc 46 || defined(TARGET_NUCLEO_F411RE) || defined(TARGET_NUCLEO_F334R8) || defined(TARGET_NUCLEO_F072RB) \
hudakz 6:14d70104b0fc 47 || defined(TARGET_NUCLEO_F091RC) || defined(TARGET_NUCLEO_F303RE) || defined(TARGET_NUCLEO_F070RB) \
hudakz 6:14d70104b0fc 48 || defined(TARGET_KL25Z ) || defined(TARGET_KL46Z) || defined(TARGET_K64F) || defined(TARGET_KL05Z) \
hudakz 6:14d70104b0fc 49 || defined(TARGET_K20D50M) || defined(TARGET_K22F) \
hudakz 6:14d70104b0fc 50 || defined(TARGET_NRF51822) \
hudakz 6:14d70104b0fc 51 || defined(TARGET_RZ_A1H)
hudakz 6:14d70104b0fc 52 SPI spi(D11, D12, D13); // MOSI, MISO, SCK
hudakz 6:14d70104b0fc 53 DigitalOut cs(D6); // CSN (select SPI chip/slave)
hudakz 6:14d70104b0fc 54 DigitalOut ce(D7); // CE (enable nRF24L01 chip)
hudakz 6:14d70104b0fc 55 DS1820 ds1820(D8); // create a ds1820 sensor
hudakz 0:6f3139e3410e 56
hudakz 0:6f3139e3410e 57 // If your board/plaform is not present yet then uncomment
hudakz 4:b3c5c54cfd21 58 // the following five 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 59
hudakz 0:6f3139e3410e 60 //#elif defined(TARGET_YOUR_BOARD)
hudakz 0:6f3139e3410e 61 //SPI spi(SPI_MOSI, SPI_MISO, SPI_SCK);
hudakz 0:6f3139e3410e 62 //DigitalOut cs(SPI_CS); // CSN (select SPI chip/slave)
hudakz 0:6f3139e3410e 63 //DigitalOut cs(CE_PIN); // CE (enable nRF24L01+ chip)
hudakz 4:b3c5c54cfd21 64 //DS1820 ds1820(DS1820_DATA_PIN);// create a ds1820 sensor
hudakz 0:6f3139e3410e 65
hudakz 0:6f3139e3410e 66 #endif
hudakz 0:6f3139e3410e 67
hudakz 0:6f3139e3410e 68 uint8_t buf[32];
hudakz 0:6f3139e3410e 69
hudakz 0:6f3139e3410e 70 /**
hudakz 4:b3c5c54cfd21 71 * @brief Implements CRC with LFSR
hudakz 0:6f3139e3410e 72 * @note
hudakz 4:b3c5c54cfd21 73 * @param data: packet data
hudakz 4:b3c5c54cfd21 74 * len: packet length
hudakz 4:b3c5c54cfd21 75 * dst: destination/location of CRC
hudakz 0:6f3139e3410e 76 * @retval
hudakz 0:6f3139e3410e 77 */
hudakz 0:6f3139e3410e 78 void bleCRC(const uint8_t* data, uint8_t len, uint8_t* dst) {
hudakz 0:6f3139e3410e 79 uint8_t v, t, d;
hudakz 0:6f3139e3410e 80
hudakz 0:6f3139e3410e 81 while(len--) {
hudakz 0:6f3139e3410e 82 d = *data++;
hudakz 0:6f3139e3410e 83 for(v = 0; v < 8; v++, d >>= 1) {
hudakz 0:6f3139e3410e 84 t = dst[0] >> 7;
hudakz 0:6f3139e3410e 85 dst[0] <<= 1;
hudakz 0:6f3139e3410e 86 if(dst[1] & 0x80)
hudakz 0:6f3139e3410e 87 dst[0] |= 1;
hudakz 0:6f3139e3410e 88 dst[1] <<= 1;
hudakz 0:6f3139e3410e 89 if(dst[2] & 0x80)
hudakz 0:6f3139e3410e 90 dst[1] |= 1;
hudakz 0:6f3139e3410e 91 dst[2] <<= 1;
hudakz 0:6f3139e3410e 92
hudakz 0:6f3139e3410e 93 if(t != (d & 1)) {
hudakz 0:6f3139e3410e 94 dst[2] ^= 0x5B;
hudakz 0:6f3139e3410e 95 dst[1] ^= 0x06;
hudakz 0:6f3139e3410e 96 }
hudakz 0:6f3139e3410e 97 }
hudakz 0:6f3139e3410e 98 }
hudakz 0:6f3139e3410e 99 }
hudakz 0:6f3139e3410e 100
hudakz 0:6f3139e3410e 101 /**
hudakz 4:b3c5c54cfd21 102 * @brief Reverses bit order in a single byte
hudakz 0:6f3139e3410e 103 * @note
hudakz 4:b3c5c54cfd21 104 * @param a: byte to be reveresed
hudakz 4:b3c5c54cfd21 105 * @retval byte with reveresed bit order
hudakz 0:6f3139e3410e 106 */
hudakz 0:6f3139e3410e 107 uint8_t swapBits(uint8_t a) {
hudakz 0:6f3139e3410e 108 uint8_t v = 0;
hudakz 0:6f3139e3410e 109 if(a & 0x80)
hudakz 0:6f3139e3410e 110 v |= 0x01;
hudakz 0:6f3139e3410e 111 if(a & 0x40)
hudakz 0:6f3139e3410e 112 v |= 0x02;
hudakz 0:6f3139e3410e 113 if(a & 0x20)
hudakz 0:6f3139e3410e 114 v |= 0x04;
hudakz 0:6f3139e3410e 115 if(a & 0x10)
hudakz 0:6f3139e3410e 116 v |= 0x08;
hudakz 0:6f3139e3410e 117 if(a & 0x08)
hudakz 0:6f3139e3410e 118 v |= 0x10;
hudakz 0:6f3139e3410e 119 if(a & 0x04)
hudakz 0:6f3139e3410e 120 v |= 0x20;
hudakz 0:6f3139e3410e 121 if(a & 0x02)
hudakz 0:6f3139e3410e 122 v |= 0x40;
hudakz 0:6f3139e3410e 123 if(a & 0x01)
hudakz 0:6f3139e3410e 124 v |= 0x80;
hudakz 0:6f3139e3410e 125 return v;
hudakz 0:6f3139e3410e 126 }
hudakz 0:6f3139e3410e 127
hudakz 0:6f3139e3410e 128 /**
hudakz 4:b3c5c54cfd21 129 * @brief Implements whitening with LFSR
hudakz 0:6f3139e3410e 130 * @note
hudakz 4:b3c5c54cfd21 131 * @param data: location of the data to be whiten
hudakz 4:b3c5c54cfd21 132 * len: data length
hudakz 4:b3c5c54cfd21 133 * whitenCoeff: whitening coefficient
hudakz 0:6f3139e3410e 134 * @retval
hudakz 0:6f3139e3410e 135 */
hudakz 0:6f3139e3410e 136 void bleWhiten(uint8_t* data, uint8_t len, uint8_t whitenCoeff) {
hudakz 0:6f3139e3410e 137 uint8_t m;
hudakz 0:6f3139e3410e 138 while(len--) {
hudakz 0:6f3139e3410e 139 for(m = 1; m; m <<= 1) {
hudakz 0:6f3139e3410e 140 if(whitenCoeff & 0x80) {
hudakz 0:6f3139e3410e 141 whitenCoeff ^= 0x11;
hudakz 0:6f3139e3410e 142 (*data) ^= m;
hudakz 0:6f3139e3410e 143 }
hudakz 0:6f3139e3410e 144
hudakz 0:6f3139e3410e 145 whitenCoeff <<= 1;
hudakz 0:6f3139e3410e 146 }
hudakz 0:6f3139e3410e 147
hudakz 0:6f3139e3410e 148 data++;
hudakz 0:6f3139e3410e 149 }
hudakz 0:6f3139e3410e 150 }
hudakz 0:6f3139e3410e 151
hudakz 0:6f3139e3410e 152 /**
hudakz 4:b3c5c54cfd21 153 * @brief Starts whitening
hudakz 4:b3c5c54cfd21 154 * @note the value we actually use is what BT'd use left shifted one...makes our life easier
hudakz 4:b3c5c54cfd21 155 * @param chan: BT channel
hudakz 4:b3c5c54cfd21 156 * @retval single byte
hudakz 0:6f3139e3410e 157 */
hudakz 0:6f3139e3410e 158 static inline uint8_t bleWhitenStart(uint8_t chan) {
hudakz 0:6f3139e3410e 159 return swapBits(chan) | 2;
hudakz 0:6f3139e3410e 160 }
hudakz 0:6f3139e3410e 161
hudakz 0:6f3139e3410e 162 /**
hudakz 4:b3c5c54cfd21 163 * @brief Assembles the packet to be transmitted
hudakz 0:6f3139e3410e 164 * @note
hudakz 4:b3c5c54cfd21 165 * @param data: packet data
hudakz 4:b3c5c54cfd21 166 * len: packet length
hudakz 4:b3c5c54cfd21 167 * dst: BLE channel
hudakz 0:6f3139e3410e 168 * @retval
hudakz 0:6f3139e3410e 169 */
hudakz 0:6f3139e3410e 170 void blePacketEncode(uint8_t* packet, uint8_t len, uint8_t chan) {
hudakz 0:6f3139e3410e 171 // Length is of packet, including crc. pre-populate crc in packet with initial crc value!
hudakz 0:6f3139e3410e 172 uint8_t i, dataLen = len - 3;
hudakz 0:6f3139e3410e 173 bleCRC(packet, dataLen, packet + dataLen);
hudakz 0:6f3139e3410e 174 for(i = 0; i < 3; i++, dataLen++)
hudakz 0:6f3139e3410e 175 packet[dataLen] = swapBits(packet[dataLen]);
hudakz 0:6f3139e3410e 176 bleWhiten(packet, len, bleWhitenStart(chan));
hudakz 0:6f3139e3410e 177 for(i = 0; i < len; i++)
hudakz 0:6f3139e3410e 178 packet[i] = swapBits(packet[i]); // the byte order of the packet should be reversed as well
hudakz 0:6f3139e3410e 179 }
hudakz 0:6f3139e3410e 180
hudakz 0:6f3139e3410e 181 /**
hudakz 4:b3c5c54cfd21 182 * @brief Sends cmommand to nRF24L01
hudakz 0:6f3139e3410e 183 * @note
hudakz 4:b3c5c54cfd21 184 * @param cmd: Command
hudakz 4:b3c5c54cfd21 185 * data: Data associated with the command
hudakz 0:6f3139e3410e 186 * @retval
hudakz 0:6f3139e3410e 187 */
hudakz 0:6f3139e3410e 188 void nrfCmd(uint8_t cmd, uint8_t data) {
hudakz 0:6f3139e3410e 189
hudakz 0:6f3139e3410e 190 // Write to nRF24's register
hudakz 0:6f3139e3410e 191
hudakz 0:6f3139e3410e 192 cs = 0;
hudakz 0:6f3139e3410e 193 spi.write(cmd);
hudakz 0:6f3139e3410e 194 spi.write(data);
hudakz 0:6f3139e3410e 195 cs = 1;
hudakz 0:6f3139e3410e 196 }
hudakz 0:6f3139e3410e 197
hudakz 0:6f3139e3410e 198 /**
hudakz 4:b3c5c54cfd21 199 * @brief Transfers one byte to nRF24L01
hudakz 0:6f3139e3410e 200 * @note
hudakz 4:b3c5c54cfd21 201 * @param cmd: the byte to be transferred
hudakz 0:6f3139e3410e 202 * @retval
hudakz 0:6f3139e3410e 203 */
hudakz 0:6f3139e3410e 204 void nrfWriteByte(uint8_t cmd) {
hudakz 0:6f3139e3410e 205 // transfer only one byte
hudakz 0:6f3139e3410e 206 cs = 0;
hudakz 0:6f3139e3410e 207 spi.write(cmd);
hudakz 0:6f3139e3410e 208 cs = 1;
hudakz 0:6f3139e3410e 209 }
hudakz 0:6f3139e3410e 210
hudakz 0:6f3139e3410e 211 /**
hudakz 4:b3c5c54cfd21 212 * @brief Transfers several bytes to nRF24L01
hudakz 0:6f3139e3410e 213 * @note
hudakz 4:b3c5c54cfd21 214 * @param data: location of bytes to be transferred
hudakz 4:b3c5c54cfd21 215 * len: number of bytes to be transferred
hudakz 0:6f3139e3410e 216 * @retval
hudakz 0:6f3139e3410e 217 */
hudakz 0:6f3139e3410e 218 void nrfWriteBytes(uint8_t* data, uint8_t len) {
hudakz 0:6f3139e3410e 219 // transfer several bytes in a row
hudakz 0:6f3139e3410e 220 cs = 0;
hudakz 0:6f3139e3410e 221 do
hudakz 0:6f3139e3410e 222 {
hudakz 0:6f3139e3410e 223 spi.write(*data++);
hudakz 0:6f3139e3410e 224 } while(--len);
hudakz 0:6f3139e3410e 225 cs = 1;
hudakz 0:6f3139e3410e 226 }
hudakz 0:6f3139e3410e 227
hudakz 0:6f3139e3410e 228 int main() {
hudakz 5:448e87318747 229 static const uint8_t chRf[] = { 2, 26, 80 };
hudakz 5:448e87318747 230 static const uint8_t chLe[] = { 37, 38, 39 };
hudakz 5:448e87318747 231
hudakz 5:448e87318747 232 uint8_t i = 0;
hudakz 5:448e87318747 233 uint8_t j = 0;
hudakz 5:448e87318747 234 uint8_t ch = 0;
hudakz 5:448e87318747 235 uint8_t data[4];
hudakz 5:448e87318747 236 float* temp = reinterpret_cast <float*>(&data[0]);
hudakz 6:14d70104b0fc 237 int error = 0;
hudakz 0:6f3139e3410e 238
hudakz 0:6f3139e3410e 239 // Chip must be deselected
hudakz 0:6f3139e3410e 240 cs = 1;
hudakz 0:6f3139e3410e 241
hudakz 0:6f3139e3410e 242 // Setup the spi for 8 bit data, high steady state clock,
hudakz 0:6f3139e3410e 243 // second edge capture, with a 10MHz clock rate
hudakz 0:6f3139e3410e 244 spi.format(8,0);
hudakz 0:6f3139e3410e 245 spi.frequency(10000000);
hudakz 0:6f3139e3410e 246
hudakz 0:6f3139e3410e 247 ce = 0;
hudakz 0:6f3139e3410e 248
hudakz 0:6f3139e3410e 249 // Initialize nRF24L01+, setting general parameters
hudakz 0:6f3139e3410e 250 nrfCmd(0x20, 0x12); // on, no crc, int on RX/TX done
hudakz 0:6f3139e3410e 251 nrfCmd(0x21, 0x00); // no auto-acknowledge
hudakz 0:6f3139e3410e 252 nrfCmd(0x22, 0x00); // no RX
hudakz 0:6f3139e3410e 253 nrfCmd(0x23, 0x02); // 4-byte address
hudakz 0:6f3139e3410e 254 nrfCmd(0x24, 0x00); // no auto-retransmit
hudakz 0:6f3139e3410e 255 nrfCmd(0x26, 0x06); // 1MBps at 0dBm
hudakz 0:6f3139e3410e 256 nrfCmd(0x27, 0x3E); // clear various flags
hudakz 0:6f3139e3410e 257 nrfCmd(0x3C, 0x00); // no dynamic payloads
hudakz 0:6f3139e3410e 258 nrfCmd(0x3D, 0x00); // no features
hudakz 0:6f3139e3410e 259 nrfCmd(0x31, 32); // always RX 32 bytes
hudakz 0:6f3139e3410e 260 nrfCmd(0x22, 0x01); // RX on pipe 0
hudakz 0:6f3139e3410e 261
hudakz 0:6f3139e3410e 262 // Set access addresses (TX address in nRF24L01) to BLE advertising 0x8E89BED6
hudakz 0:6f3139e3410e 263 // Remember that both bit and byte orders are reversed for BLE packet format
hudakz 0:6f3139e3410e 264 buf[0] = 0x30;
hudakz 0:6f3139e3410e 265 buf[1] = swapBits(0x8E);
hudakz 0:6f3139e3410e 266 buf[2] = swapBits(0x89);
hudakz 0:6f3139e3410e 267 buf[3] = swapBits(0xBE);
hudakz 0:6f3139e3410e 268 buf[4] = swapBits(0xD6);
hudakz 0:6f3139e3410e 269 nrfWriteBytes(buf, 5);
hudakz 0:6f3139e3410e 270 buf[0] = 0x2A; // set RX address in nRF24L01, doesn't matter because RX is ignored in this case
hudakz 0:6f3139e3410e 271 nrfWriteBytes(buf, 5);
hudakz 4:b3c5c54cfd21 272
hudakz 3:96153a5d95f6 273 if(!ds1820.begin()) {
hudakz 3:96153a5d95f6 274 #if DEBUG
hudakz 3:96153a5d95f6 275 serial.printf("No DS1820 sensor found!\r\n");
hudakz 3:96153a5d95f6 276 #endif
hudakz 4:b3c5c54cfd21 277 return 1;
hudakz 3:96153a5d95f6 278 }
hudakz 0:6f3139e3410e 279
hudakz 4:b3c5c54cfd21 280
hudakz 5:448e87318747 281 while(1) {
hudakz 6:14d70104b0fc 282 ds1820.startConversion(); // Start temperature conversion
hudakz 6:14d70104b0fc 283 wait(1.0); // let DS1820 complete the temperature conversion
hudakz 6:14d70104b0fc 284 error = ds1820.read(*temp); // read temperature from DS1820 and perform cyclic redundancy check (CRC)
hudakz 2:4f285d1d5c1f 285
hudakz 2:4f285d1d5c1f 286 #if DEBUG
hudakz 6:14d70104b0fc 287 switch(error) {
hudakz 6:14d70104b0fc 288 case 0: // no errors -> '*temp' contains the value of measured temperature
hudakz 6:14d70104b0fc 289 serial.printf("temp = %3.1f\r\n", *temp);
hudakz 6:14d70104b0fc 290 break;
hudakz 6:14d70104b0fc 291 case 1: // no sensor present -> '*temp' is not updated
hudakz 6:14d70104b0fc 292 serial.printf("no sensor present\n\r");
hudakz 6:14d70104b0fc 293 break;
hudakz 6:14d70104b0fc 294 case 2: // CRC error -> '*temp' is not updated
hudakz 6:14d70104b0fc 295 serial.printf("CRC error\r\n");
hudakz 6:14d70104b0fc 296 }
hudakz 2:4f285d1d5c1f 297 #endif
hudakz 7:79c3ff270db1 298
hudakz 7:79c3ff270db1 299 for(ch = 0; ch < (sizeof(chRf) / sizeof(*chRf)); ch++) {
hudakz 7:79c3ff270db1 300 i = 0;
hudakz 7:79c3ff270db1 301 buf[i++] = 0x42; // PDU type, given address is random; 0x42 for Android and 0x40 for iPhone
hudakz 7:79c3ff270db1 302 buf[i++] = 25; // number of following data bytes, max 29 (CRC is not included)
hudakz 7:79c3ff270db1 303
hudakz 7:79c3ff270db1 304 //----------------------------
hudakz 7:79c3ff270db1 305 buf[i++] = MY_MAC_0;
hudakz 7:79c3ff270db1 306 buf[i++] = MY_MAC_1;
hudakz 7:79c3ff270db1 307 buf[i++] = MY_MAC_2;
hudakz 7:79c3ff270db1 308 buf[i++] = MY_MAC_3;
hudakz 7:79c3ff270db1 309 buf[i++] = MY_MAC_4;
hudakz 7:79c3ff270db1 310 buf[i++] = MY_MAC_5;
hudakz 0:6f3139e3410e 311
hudakz 7:79c3ff270db1 312 buf[i++] = 2; // flags (LE-only, limited discovery mode)
hudakz 7:79c3ff270db1 313 buf[i++] = 0x01;
hudakz 7:79c3ff270db1 314 buf[i++] = 0x05;
hudakz 7:79c3ff270db1 315
hudakz 7:79c3ff270db1 316 buf[i++] = 9; // length of the name, including type byte
hudakz 7:79c3ff270db1 317 buf[i++] = 0x08; // TYPE_NAME_SHORT
hudakz 7:79c3ff270db1 318 buf[i++] = 'n';
hudakz 7:79c3ff270db1 319 buf[i++] = 'R';
hudakz 7:79c3ff270db1 320 buf[i++] = 'F';
hudakz 7:79c3ff270db1 321 buf[i++] = '2';
hudakz 7:79c3ff270db1 322 buf[i++] = '4';
hudakz 7:79c3ff270db1 323 buf[i++] = 'L';
hudakz 7:79c3ff270db1 324 buf[i++] = '0';
hudakz 7:79c3ff270db1 325 buf[i++] = '1';
hudakz 7:79c3ff270db1 326
hudakz 7:79c3ff270db1 327 buf[i++] = 5; // length of custom data, including type byte
hudakz 7:79c3ff270db1 328 buf[i++] = 0xff; // TYPE_CUSTOMDATA
hudakz 0:6f3139e3410e 329
hudakz 7:79c3ff270db1 330 buf[i++] = data[0]; // temperature floating point value (four bytes)
hudakz 7:79c3ff270db1 331 buf[i++] = data[1];
hudakz 7:79c3ff270db1 332 buf[i++] = data[2];
hudakz 7:79c3ff270db1 333 buf[i++] = data[3];
hudakz 7:79c3ff270db1 334 //----------------------------
hudakz 7:79c3ff270db1 335
hudakz 7:79c3ff270db1 336 buf[i++] = 0x55; // CRC start value: 0x555555
hudakz 7:79c3ff270db1 337 buf[i++] = 0x55;
hudakz 7:79c3ff270db1 338 buf[i++] = 0x55;
hudakz 0:6f3139e3410e 339
hudakz 7:79c3ff270db1 340 nrfCmd(0x25, chRf[ch]);
hudakz 7:79c3ff270db1 341 nrfCmd(0x27, 0x6E); // Clear flags
hudakz 7:79c3ff270db1 342 blePacketEncode(buf, i, chLe[ch]);
hudakz 7:79c3ff270db1 343 nrfWriteByte(0xE2); // Clear RX Fifo
hudakz 7:79c3ff270db1 344 nrfWriteByte(0xE1); // Clear TX Fifo
hudakz 7:79c3ff270db1 345
hudakz 7:79c3ff270db1 346 cs = 0;
hudakz 7:79c3ff270db1 347 spi.write(0xA0);
hudakz 7:79c3ff270db1 348 for(j = 0; j < i; j++)
hudakz 7:79c3ff270db1 349 spi.write(buf[j]);
hudakz 7:79c3ff270db1 350 cs = 1;
hudakz 2:4f285d1d5c1f 351
hudakz 7:79c3ff270db1 352 nrfCmd(0x20, 0x12); // TX on
hudakz 7:79c3ff270db1 353 ce = 1; // Enable Chip
hudakz 7:79c3ff270db1 354 wait_ms(50);
hudakz 7:79c3ff270db1 355 ce = 0; // (in preparation of switching to RX quickly)
hudakz 7:79c3ff270db1 356 }
hudakz 0:6f3139e3410e 357 }
hudakz 0:6f3139e3410e 358 }