BLE Communication between two nrf5340

Hi, 

You can start from 

• Bluetooth: Central UART
• Bluetooth: Peripheral UART

Regards,
Amanda

Hi Amanda

thank you very much for the tips.

While testing those samples, I can't get any output, that the Kits are connected. I only get a message "Starting Bluetooth Central UART example" in NRF TERMINAL, but nothing else. On the Kit with the Peripheral sample on it indicates the LED 2 that the Kit is connected, but in NRF TERMINAL is also only the "Starting Nordic UART service example" message. I also connected PuTTy to the Central, but I don!'t get any message here. I did not change anything in the Samples so far.

Could you please give me an advice, what should I do?

Regards, Jirik

Hi Amanda

thank you for advice. I have still problems with the received data. 

This is how is changed the ble_write_thread, I just added array number and variable length, and I'm increasing the number everz second and send it to the central.

uint8_t number[1];
uint16_t length;

void ble_write_thread(void)
{
	/* Don't go any further until BLE is initialized */
	k_sem_take(&ble_init_ok, K_FOREVER);
	length = sizeof(number);
	number[0] = 0b0000001;
	for (;;) {
		if (bt_nus_send(NULL, number, length)) {
			LOG_WRN("Failed to send data over BLE connection");
		}
		number[0] ++;
		length = sizeof(number);
		k_msleep(1000);
		printk("number %x\t length %x\n", number[0], length);
	}
}

The output in PuTTy of the peripheral looks like this: 

Starting Nordic UART service example

number 2         length 1

number 3         length 1

number 4         length 1

number 5         length 1

When I do no changes to the central, the UART outputs in PuTTy are characters, which I do not need, I need the numbers, so I made following change.

static uint8_t ble_data_received(struct bt_nus_client *nus,
						uint8_t *data, uint16_t len)
{
	ARG_UNUSED(nus);

	printk("%x\n", &data);
	
	return BT_GATT_ITER_CONTINUE;
}

In the central I just let the received data print to console like this (without sending it to UART).

But now I don't get the data I send, I get something like this: 

20003b94

20003b94

20003b94

20003b94

20003b94

20003b94

20003b94

20003b94

Some data, I don't understand, and every time same. How is it possible?

I think in the central I work with wrong data, but I can't find the right.

I also tried another sample, peripheral_hr and central_hr, I think this programm does the same thing as I tried, the peripheral sends every second increased number, and the central should receive it and print it, but it prints every time the same number.

PuTTy - Peripheral

Heartrate 141

Heartrate 142

Heartrate 143

Heartrate 144

Heartrate 145

Heartrate 146

Heartrate 147

Heartrate 148

Heartrate 149

PuTTy - Central

[NOTIFICATION] data 20005dc0 length 2

[NOTIFICATION] data 20005dc0 length 2

[NOTIFICATION] data 20005dc0 length 2

[NOTIFICATION] data 20005dc0 length 2

[NOTIFICATION] data 20005dc0 length 2

[NOTIFICATION] data 20005dc0 length 2

[NOTIFICATION] data 20005dc0 length 2

[NOTIFICATION] data 20005dc0 length 2

[NOTIFICATION] data 20005dc0 length 2

I think it must be some other parameter read.

Could you please give me an advice, how do I get to the data, I actually wanted to send?

Jiri

I just solved the issue with the output, I completely forgot that data is an array, so i need to print it like

printk("%x\n", data[0]);

Just a beginners mistake :D

Happy to know you fix the issue. 

-Amanda

Hello Amanda

I'm now trying to set the directed advertising on the peripheral, so it accepts only connections request from my peer, but I can't find, in which format should i set the address of the central. I tried to change it this way in peripheral main, but it did not connect.

err = bt_le_adv_start(((struct bt_le_adv_param[]) { 
{ .id = BT_ID_DEFAULT, .sid = 0, .secondary_max_skip = 0, 
.options = (BT_LE_ADV_OPT_CONNECTABLE), .interval_min = (0x00a0), 
.interval_max = (0x00f0), .peer = {0xF0,0x33,0x4D,0x3A,0x9F,0x6B}, } }),
ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));

I am also a little bit confused of the Bluetooth LE Device Adress in addr.h library.

/** Bluetooth Device Address */
typedef struct {
	uint8_t  val[BT_ADDR_SIZE];
} bt_addr_t;
/**/

/** Length in bytes of an LE Bluetooth address. Not packed, so no sizeof() */
#define BT_ADDR_LE_SIZE 7
/** Bluetooth LE Device Address */
typedef struct {
	uint8_t      type;
	bt_addr_t a;
} bt_addr_le_t;

What does the variable type mean and in which way should I write the bt_addr_t?

Here is the log from J-Link RTT Viewer

00> [00:00:00.272,583] <inf> fs_nvs: 2 Sectors of 4096 bytes
00> [00:00:00.272,583] <inf> fs_nvs: alloc wra: 0, fc8
00> [00:00:00.272,583] <inf> fs_nvs: data wra: 0, 2c
00> [00:00:00.300,354] <inf> bt_hci_core: No ID address. App must call settings_load()
00> [00:00:00.300,354] <inf> peripheral_uart: Bluetooth initialized
00> [00:00:00.949,981] <inf> peripheral_uart: Connected F0:33:4D:3A:9F:6B (random)
00> [00:00:01.664,978] <wrn> peripheral_uart: Failed to send data over BLE connection

Sorry for maybe stupid questions, I am just beginner and did not find it anywhere.

Hi, 

Please create a new support case since this issue is away from the original scope. 

-Amanda

Hi, 

Please create a new support case since this issue is away from the original scope. 

-Amanda