BLE Discovery Service Can Not Find Service

RE: BLE Discovery Service Can Not Find Service

Simonr — Mon, 04 Apr 2022 07:40:18 GMT

Sorry about the late reply, but I've been out of office most of last week and I'm just now catching up to my backlog.

I don't think these issues come from the scan filter you're using, as it seems specifically related to the discovery manager. Are you sure you didn't change anything in the discovery procedure at all? If not, is the NUS service actually advertised by the peripheral. The nRFConnect app searches for all kinds of services which is also why it takes longer, while the central UART should only care about the NUS service. This still doesn't explain why the central isn't able to discover the NUS service.

The "NULL attribute" message points to the discovery callback not getting any attributes, so I guess the peripheral isn't providing these to the central for some reason.

Best regards,

Simon

RE: BLE Discovery Service Can Not Find Service

ctzn — Tue, 29 Mar 2022 06:17:56 GMT

Hi,

The change I made in the uart_central sample is below.

#define DEVICE_NAME	"TFT100_LE"
.
.
.

static int scan_init(void)
{
    .
    .
    .
	err = bt_scan_filter_add(BT_SCAN_FILTER_TYPE_NAME, DEVICE_NAME);
	if (err) {
		LOG_ERR("Scanning name filter cannot be set (err %d)", err);
		return err;
	}

	err = bt_scan_filter_enable(BT_SCAN_NAME_FILTER, false);
	if (err) {
		LOG_ERR("Name Filter cannot be turned on (err %d)", err);
		return err;
	}
		
	LOG_INF("Scan module initialized");
	return err;
}

There is only 1 piece of hardware with this BLE name in my environment.

The services seen in the nRF connect application on android for the peripheral device are shown in the screenshot below.

In addition, the records in the nRF Logger in android are listed below. It says services discovered about 550 milliseconds after service discovery. In the central_uart sample, service discover does not wait this long.

RE: BLE Discovery Service Can Not Find Service

Simonr — Tue, 29 Mar 2022 06:03:45 GMT

Can you show me what exact changes you made to the filter on the central side? Are you sure there aren't more than one peripheral device with the name you're scanning for? And can you confirm whether the peripheral device is based on the peripheral_uart sample project and does indeed have the NUS service implemented?

Best regards,

Simon