Hi , Thanks for your advice. I compiled the code below into nrf51 dongle 1, and pure scan code to nrf51 dongle 2 to check if nrf51 dongle 1 constantly transmitting signal. Transmitting part of nrf51 dongle 1 - nrf51 dongle 2 (with the pure scan code) is able to detect signal from nrf51 dongle 1 for a period of time then stop receiving after that. Scanning part of nrf51 dongle 1 - I tested the nrf51 dongle 1 scan part by tranmistting ibeacon from my phone app, and the nrf51 dongle 1 can receive without any problem on teraterm. Can you help on this?

1. include "mbed.h"
2. include "BLE.h"
3. include "iBeaconScan.h"
4. include "ble/services/iBeacon.h"

Serial pc(TX_PIN_NUMBER, RX_PIN_NUMBER); DigitalOut led1(LED1); union unionType u;

uint8_t RX_Flag = 0; int R_S_S_I;

BLE ble;

void bleInitComplete(BLE::InitializationCompleteCallbackContext *params) { BLE &ble = params->ble; ble_error_t error = params->error;

if (error != BLE_ERROR_NONE) { return; }

/**

• The Beacon payload has the following composition:
• 128-Bit / 16byte UUID = E2 0A 39 F4 73 F5 4B C4 A1 2F 17 D1 AD 07 A9 61
• Major/Minor = 0x1122 / 0x3344
• Tx Power = 0xC8 = 200, 2's compliment is 256-200 = (-56dB)
• Note: please remember to calibrate your beacons TX Power for more accurate results.
• / const uint8_t uuid[] = {0xE4, 0x0A, 0x39, 0xF4, 0x73, 0xF5, 0x4B, 0xC4, 0xA1, 0x2F, 0x17, 0xD1, 0xAD, 0x07, 0xA9, 0x61}; uint16_t majorNumber = 3344; uint16_t minorNumber = 4455; uint16_t txPower = 0xC8; iBeacon *ibeacon = new iBeacon(ble, uuid, majorNumber, minorNumber, txPower);

ble.gap().setAdvertisingInterval(150); /* 150ms. */

}

void AdvertisementReportCallback(const Gap::AdvertisementCallbackParams_t *params) { led1 = !led1; printf("Advertisement packet received.\r\n"); uint8_t i;

memset(u.rawData, 0 , sizeof(u.rawData)); memcpy(u.rawData, params->advertisingData,params->advertisingDataLen);

printf("uuid:"); for( i = 0; i < 16; i++){ printf("%02x ",u.iBeaconPayload_m.uuid[i]); }

printf("\r\n"); printf("majorNumber:%02x %02x\r\n",u.iBeaconPayload_m.majorNumber[0], u.iBeaconPayload_m.majorNumber[1]); printf("minorNumber:%02x %02x\r\n",u.iBeaconPayload_m.minorNumber[0], u.iBeaconPayload_m.minorNumber[1]); printf("txPower:%d\r\n",u.iBeaconPayload_m.txPower); printf("RSSI:%d\r\n",params->rssi);

}

int main(void) { ble.init(bleInitComplete); while (!ble.hasInitialized()) { /* spin loop */ }

iBeaconInit();

while(1) { ble.gap().startAdvertising(); wait(20); ble.gap().stopAdvertising();

iBeaconStartScan(); wait(130); iBeaconStopScan(); } }