nrf 5340 for Bluetooth low energy

[Marwa Sabbagh]

Hi!

This tutorial is just for current > Measuring current. I want the same for latency with code. 

I'm working with two nrf5340 for Bluetooth low energy and I want to measure latency value between those cards using oscilloscope. Is there any sample code that I can use to send data  and receive it in the other cord. I want to allow  one bin in the first nrf5340 to write data and a bin in the other nrf5340 to read this data. 

2. I also want to measure RSSI. Is is possible to do that using the same method. I mean that I want to measure RSSI when the two cards are connected to each other.

Best regards  

[Hung Bui]

I want the same for latency with code. 

I'm working with two nrf5340 for Bluetooth low energy and I want to measure latency value between those cards using oscilloscope.

 Could you please explain what exactly you meant by "measure latency value between those cards" ? 

If you want to track the communication between two device over the air you can use the nRF sniffer. 

The latency between a packet sent and when it's received on the peer device depends on the connection interval, slave latency and if there is any other packets to be sent queued before the current packet. 

2. If you want to measure RSSI of the advertising packet, you have that report in the bt_le_scan_recv_info  *device_inf in the scan callbacks. 

When you are in a connection I'm not so sure how you can get it, but I found some config here that maybe related. 

[Marwa Sabbagh]

Hi!

I use this printf("%d\n",device_inf->rssi); to print RSSI value but I receive the  same value all the time  105 regardless if I change direction for other nrf5340 or not. How can i receive right value?

[Marwa Sabbagh]

Hi!

I put it in both function but I get value in  scan_filter_match() function. I still get the same value with which is not correct.  RSSI will be between 0-100 but the best result is 50 so i don't now what 105 stands for and why it never changes.

static void scan_filter_match(struct bt_scan_device_info *device_info,
			      struct bt_scan_filter_match *filter_match,
			      bool connectable)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(device_info->recv_info->addr, addr, sizeof(addr));

	LOG_INF("Filters matched. Address: %s connectable: %d",
		log_strdup(addr), connectable);
       // LOG_INF("%d\n",inf->rssi);
        printf("%d\n",inf->rssi);
}

[Hung Bui]

Please explain why you come up with "inf->rssi" ? 

What is inf variable ? 
Please study how a callback function work and the arguments come with it. 

[Marwa Sabbagh]

struct  bt_le_scan_recv_info  *inf; 

[Hung Bui]

You can't just define a  varibale and expect that it will contain some data. 

You need to use the argument in the callback, in this case device_info variable. 
Please try to print out the advertising data just to know how to access the data inside device_info. 

[Marwa Sabbagh]

I print device_info like you say and I get ø@. I try to understand the cod but in scan_filter_match()  there is no arguments that contain rssi value so what i should do. Pleas help me to print rssi value.

I find out this struct that have rssi so how can I print it if it is right to use.

struct bt_scan_adv_info {
	/** Bluetooth LE advertising type. According to
	 *  Bluetooth Specification 7.8.5
	 */
	uint8_t adv_type;

	/** Received Signal Strength Indication in dBm. */
	int8_t rssi;
};

[Hung Bui]

Try this

static void scan_filter_match(struct bt_scan_device_info *device_info,
			      struct bt_scan_filter_match *filter_match,
			      bool connectable)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(device_info->recv_info->addr, addr, sizeof(addr));
LOG_INF("Filters matched. RSSI: %d, Address: %s connectable: %d",device_info->recv_info->rssi,
		log_strdup(addr), connectable);
	
}

The log will be printed in RTT.