missing bytes in BLE advertising (Eddystone-UID)

[MartinSadovy]

Hi, I'm trying to advertise Eddystone-UID. I checked this issue with reference code example (examples/bluetooth/ble_adv).

I replaced service name sequence by Eddystone-UID sequence in example code and run it.

When byte 27 is 0x(2-0)(0-f), broadcasting sequence ends on this byte. (code below)

• Expected UID: 00000000000000000000-112233445566
• Observed UID: 00000000000000000000-112233440000

Case without problem:

• Expected UID: 00000000000000000000-112233440566
• Observed UID: 00000000000000000000-112233440566

Chip is ESP32D0WDQ6 (revision 0) Tested on master & 2.1.

static void hci_cmd_send_ble_set_adv_data()
{
    uint8_t adv_data[31] =
    {
          2,      // Len
      0x01,   // Type Flags
      0x06,   // GENERAL_DISC_MODE 0x02 | BR_EDR_NOT_SUPPORTED 0x04
      3,      // Len
      0x03,   // Type 16-Bit UUID
      0xAA,   // Eddystone UUID 2 -> 0xFEAA LSB
      0xFE,   // Eddystone UUID 1 MSB
      19,     // Length of Beacon Data
      0x16,   // Type Service Data
      0xAA,   // Eddystone UUID 2 -> 0xFEAA LSB
      0xFE, // Eddystone UUID 1 MSB
      0x00,  // Frame type: URL
      0x01, // Power - 1dbm - https://github.com/espressif/esp-idf/blob/master/components/bt/include/esp_bt.h
      0x00, // NID 0-9
      0x00,
      0x00,
      0x00,
      0x00,
      0x00,
      0x00,
      0x00,
      0x00,
      0x00,
      0x11, // BID 0-5
      0x22,
      0x33,
      0x44,
      0x55, // 0xY5 - Y >= 2
      0x66,
      0x00, //RFU
      0x00, //RFU
    };
    uint8_t adv_data_len = 31;

    uint16_t sz = make_cmd_ble_set_adv_data(hci_cmd_buf, adv_data_len, (uint8_t *)adv_data);
    esp_vhci_host_send_packet(hci_cmd_buf, sz);
}

[chegewara]

Hi @MartinSadovy I think your data lenght is too small. It should be 23 bytes and not 19 like in your code. This way client probably is trucating data to 19 bytes and then adds 2 0x00 bytes since last 2 bytes are reserved and need to be 0x00.

[MartinSadovy]

@chegewara Thank you!