the scan result is imcompleted

RE: the scan result is imcompleted

Sigurd — Mon, 04 May 2020 06:53:30 GMT

[quote user="zhengrongfan"]But the packet seems less than 31 bytes, acutally it has only 30 bytes.[/quote]

A device is still allowed to split these 30 bytes into 2 packets(regular advertising packet + scan response packet). The scan response packet is only sent when requested by the scanner. Again, If the packet that is scanned is a scan response packet, the "p_scan_evt->params.p_not_found->type.scan_response" bit field will be set to 1.

RE: the scan result is imcompleted

zhengrongfan — Thu, 30 Apr 2020 10:02:32 GMT

But the packet seems less than 31 bytes, acutally it has only 30 bytes.

RE: the scan result is imcompleted

Sigurd — Fri, 24 Apr 2020 11:44:35 GMT

[quote user="zhengrongfan"]Why does it happen? And is there any way to make it pass all the data in one NRF_BLE_SCAN_EVT_NOT_FOUND?[/quote]

The advertising packet can consist of no more than 31 bytes. Because of this limit, the advertising name and/or UUID are often placed in the scan response packet. If the packet that is scanned is a scan response packet, the "p_scan_evt->params.p_not_found->type.scan_response" bit field will be set to 1.

RE: the scan result is imcompleted

zhengrongfan — Fri, 24 Apr 2020 02:14:10 GMT

Hi,

I modify my test code and now it look likes below

static void scan_evt_handler(scan_evt_t const * p_scan_evt)
{
ret_code_t err_code;

switch(p_scan_evt->scan_evt_id)
{
case NRF_BLE_SCAN_EVT_CONNECTING_ERROR:
{
err_code = p_scan_evt->params.connecting_err.err_code;
NRF_LOG_DEBUG("connecting error = %d", err_code);
}
break;
case NRF_BLE_SCAN_EVT_NOT_FOUND:
{
uint8_t addr[] = {0x01, 0x86, 0xAD, 0xC2, 0x1F, 0xE2};
if(!memcmp(addr, p_scan_evt->params.p_not_found->peer_addr.addr, 6))
{
NRF_LOG_DEBUG("address matched");
NRF_LOG_HEXDUMP_DEBUG(p_scan_evt->params.p_not_found->data.p_data, p_scan_evt->params.p_not_found->data.len);
}

...

}

And the result shows the adv is divided into two NRF_BLE_SCAN_EVT_NOT_FOUND events:

00> <debug> app: address matched
00>
00> <debug> app: 02 01 06 14 16 FF CB 11|........
00>
00> <debug> app: 3C 01 27 11 19 35 94 26|<.'..5.&
00>
00> <debug> app: 04 0A 3C 17 D4 00 00 00|..<.....
00>
00> <debug> app: address matched
00>
00> <debug> app: 05 08 52 54 5F 54 |..RT_T

The second one is its name.

Why does it happen? And is there any way to make it pass all the data in one NRF_BLE_SCAN_EVT_NOT_FOUND?

Thank you.

RE: the scan result is imcompleted

Sigurd — Thu, 23 Apr 2020 11:11:17 GMT

Hi,

[quote user=""]However, it only finds the first two types, as below,[/quote]

How does your scan-parsing code look like ?