Bluetooth disconnects when notification enabled

RE: Bluetooth disconnects when notification enabled

bscdb — Mon, 23 Sep 2019 04:57:56 GMT

Yes you're absolutely correct! That was the problem.. :) Thanks!

RE: Bluetooth disconnects when notification enabled

Edvin — Thu, 19 Sep 2019 11:56:44 GMT

Ah, that is the issue:

[quote user="bop123"]I used nrf52 for above code & nrf51 DK with nrfConnect[/quote]

The nRF51 doesn't support an MTU > 20 bytes, because the S130 softdevice does not support this. Try to use an nRF52DK with nRF connect as well (or try to use a phone that you know supports this. Even though MTU > 20 is part of the BLE spec, it is optional to support this, so not all phones support this either, but if you have a fairly new phone, you can test it with nRF Connect for Mobile.

What Microsoft's BLE Explorer tool supports, I don't know. You will have to check with them.

Best regards,

Edvin

RE: Bluetooth disconnects when notification enabled

bscdb — Thu, 19 Sep 2019 10:36:34 GMT

Nope thats strange, it does not. I also checked with my Android code & Microsoft's BLE Explorer tool. Were you consistently seeing this behavior or just one time? Did you use nrf52 DK? I used nrf52 for above code & nrf51 DK with nrfConnect & couldnt see more than 20 bytes being passed both ways. Could you please try the same or with different host code?

RE: Bluetooth disconnects when notification enabled

Edvin — Thu, 19 Sep 2019 10:29:48 GMT

I tested your project against nRF Connect for Desktop:

I was able to both receive and send 29 bytes.

Does it not behave the same in your case?

RE: Bluetooth disconnects when notification enabled

bscdb — Wed, 18 Sep 2019 14:32:38 GMT

I checked it on nrfconnect. Even I was thinking the same that I'm correctly sending 29 bytes, may be nrfconnect does not display them?

Can you check at your end if its the same?

I also receive only 20 bytes from host. So both ways its restricted to 20 bytes only.

For receiving 29 bytes, I changed the code to-

static void on_write(ble_cus_t * p_cus, ble_evt_t const * p_ble_evt)
{
	ble_gatts_evt_write_t const * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;
    // Custom Value Characteristic Written to.
    if (p_evt_write->handle == p_cus->custom_value_handles.value_handle)
    {
        nrf_gpio_pin_toggle(LED_4);
		for(int i = 0; i < p_evt_write->len; i++)
		{
			NRF_LOG_INFO("Data Received: %d", p_evt_write->data[i]);
		}
        /*if(*p_evt_write->data == 0x01)
        {
            nrf_gpio_pin_clear(LED_3);
        }
        else if(*p_evt_write->data == 0x02)
        {
            nrf_gpio_pin_set(LED_3);
        }
        else
        {
          //Do nothing
        }*/
    }
    // Check if the Custom value CCCD is written to and that the value is the appropriate length, i.e 2 bytes.
    if ((p_evt_write->handle == p_cus->custom_value_handles.cccd_handle) && (p_evt_write->len == 2))
    {
        // CCCD written, call application event handler
        if (p_cus->evt_handler != NULL)
        {
            ble_cus_evt_t evt;
            if (ble_srv_is_notification_enabled(p_evt_write->data))
            {
                evt.evt_type = BLE_CUS_EVT_NOTIFICATION_ENABLED;
            }
            else
            {
                evt.evt_type = BLE_CUS_EVT_NOTIFICATION_DISABLED;
            }
            // Call the application event handler.
            p_cus->evt_handler(p_cus, &evt);
        }
    }
}

When I send more than 20 bytes from nrfConnect, I get a message saying

When I was debugging, I got

Could you please check at your end? I cant seem to find any solution to this.

devzone.nordicsemi.com/.../ble_5F00_app_5F00_template_5F00_custom_5F00_packet.zip

I'm using SDK15.2. My thinking is that the updated MTU size is not being exchanged between peripheral & central.

RE: Bluetooth disconnects when notification enabled

Edvin — Wed, 18 Sep 2019 12:02:33 GMT

Ok. How do you determine that you are just able to send 20 bytes? I do believe you, but I want to know what symptoms you are seeing.

RE: Bluetooth disconnects when notification enabled

bscdb — Wed, 18 Sep 2019 11:30:36 GMT

Hi Edvin, I have already mentioned above that I made these changes -

#define NRF_SDH_BLE_GAP_DATA_LENGTH 36

#define NRF_SDH_BLE_GATT_MAX_MTU_SIZE 32

BLE_GATT_ATT_MTU_DEFAULT = 32 define in ble_gatt.h

may require you to change your ram settings again.

But still it does not send more than 20 bytes.

RE: Bluetooth disconnects when notification enabled

Edvin — Wed, 18 Sep 2019 08:22:09 GMT

I suggest you look into the ble_app_uart example to see how to send more than 20 bytes. Increasing these:

#define NRF_SDH_BLE_GAP_DATA_LENGTH 36

#define NRF_SDH_BLE_GATT_MAX_MTU_SIZE 32

BLE_GATT_ATT_MTU_DEFAULT = 32 define in ble_gatt.h

may require you to change your ram settings again.

[quote user="bop123"]Also how do I receive 20 bytes from host? Right now its just a byte.[/quote]

To see how to "receive more than one byte", please refer to the ble_app_uart_c example. You probably receive more than one byte, but you need to look at the length field. Please check the function ble_nus_c_evt_handler() and the event BLE_NUS_C_EVT_NUS_TX_EVT. The data is located in p_ble_nus_evt->p_data, and the length of the data is found in p_ble_nus_evt->data_len.

Best regards,

Edvin

RE: Bluetooth disconnects when notification enabled

bscdb — Tue, 17 Sep 2019 18:59:48 GMT

Hi,

The above error got fixed by referring to https://devzone.nordicsemi.com/f/nordic-q-a/34650/custom_ble_service_example---uint16_t-custom_value---nrf_error_data_size.

But now I'm able to send only 20 bytes out of 29 bytes.

Changes I made -

In sdk_config.h -----------

#define NRF_SDH_BLE_GAP_DATA_LENGTH 36

#define NRF_SDH_BLE_GATT_MAX_MTU_SIZE 32

BLE_GATT_ATT_MTU_DEFAULT = 32 define in ble_gatt.h

changed the RAM settings

static uint32_t custom_value_char_add(ble_cus_t * p_cus, const ble_cus_init_t * p_cus_init)
{
    uint32_t            err_code;
    ble_gatts_char_md_t char_md;
    ble_gatts_attr_md_t cccd_md;
    ble_gatts_attr_t    attr_char_value;
    ble_uuid_t          ble_uuid;
    ble_gatts_attr_md_t attr_md;

    // Add Custom Value characteristic
    memset(&cccd_md, 0, sizeof(cccd_md));

    //  Read  operation on cccd should be possible without authentication.
    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);

    cccd_md.write_perm = p_cus_init->custom_value_char_attr_md.cccd_write_perm;
    cccd_md.vloc       = BLE_GATTS_VLOC_STACK;

    memset(&char_md, 0, sizeof(char_md));

    char_md.char_props.read   = 1;
    char_md.char_props.write  = 1;
    char_md.char_props.notify = 1;
    char_md.p_char_user_desc  = NULL;
    char_md.p_char_pf         = NULL;
    char_md.p_user_desc_md    = NULL;
    char_md.p_cccd_md         = &cccd_md;
    char_md.p_sccd_md         = NULL;

    ble_uuid.type = p_cus->uuid_type;
    ble_uuid.uuid = CUSTOM_VALUE_CHAR_UUID;

    memset(&attr_md, 0, sizeof(attr_md));

    attr_md.read_perm  = p_cus_init->custom_value_char_attr_md.read_perm;
    attr_md.write_perm = p_cus_init->custom_value_char_attr_md.write_perm;
    attr_md.vloc       = BLE_GATTS_VLOC_STACK;
    attr_md.rd_auth    = 0;
    attr_md.wr_auth    = 0;
    attr_md.vlen       = 0;

    memset(&attr_char_value, 0, sizeof(attr_char_value));

    attr_char_value.p_uuid    = &ble_uuid;
    attr_char_value.p_attr_md = &attr_md;
    attr_char_value.init_len  = 29*sizeof(uint8_t);
    attr_char_value.init_offs = 0;
    attr_char_value.max_len   = 29*sizeof(uint8_t);

    err_code = sd_ble_gatts_characteristic_add(p_cus->service_handle, &char_md, &attr_char_value, &p_cus->custom_value_handles);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }

    return NRF_SUCCESS;
}

uint32_t ble_cus_custom_value_update(ble_cus_t * p_cus, uint8_t * custom_value)	/*NEW CHANGE*/
{
    NRF_LOG_INFO("In ble_cus_custom_value_update. \r\n");
    if (p_cus == NULL)
    {
        return NRF_ERROR_NULL;
    }
    uint32_t err_code = NRF_SUCCESS;
    ble_gatts_value_t gatts_value;
    // Initialize value struct.
    memset(&gatts_value, 0, sizeof(gatts_value));
    gatts_value.len     = 29*sizeof(uint8_t);	/*NEW CHANGE*/
    gatts_value.offset  = 0;
    gatts_value.p_value = custom_value;
    // Update database.
    err_code = sd_ble_gatts_value_set(p_cus->conn_handle, p_cus->custom_value_handles.value_handle, &gatts_value);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }
    // Send value if connected and notifying.
    if ((p_cus->conn_handle != BLE_CONN_HANDLE_INVALID))
    {
        ble_gatts_hvx_params_t hvx_params;
        memset(&hvx_params, 0, sizeof(hvx_params));
        hvx_params.handle = p_cus->custom_value_handles.value_handle;
        hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;
        hvx_params.offset = gatts_value.offset;
        hvx_params.p_len  = &gatts_value.len;
        hvx_params.p_data = gatts_value.p_value;
        err_code = sd_ble_gatts_hvx(p_cus->conn_handle, &hvx_params);
        NRF_LOG_INFO("sd_ble_gatts_hvx result: %x. \r\n", err_code);
		NRF_LOG_INFO("hvx_params.p_len: %x. \r\n", &hvx_params.p_len);
    }
    else
    {
        err_code = NRF_ERROR_INVALID_STATE;
        NRF_LOG_INFO("sd_ble_gatts_hvx result: NRF_ERROR_INVALID_STATE. \r\n");
    }
    return err_code;
}

Also how do I receive 20 bytes from host? Right now its just a byte.

static void on_write(ble_cus_t * p_cus, ble_evt_t const * p_ble_evt)
{
	ble_gatts_evt_write_t const * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;
    // Custom Value Characteristic Written to.
    if (p_evt_write->handle == p_cus->custom_value_handles.value_handle)
    {
        nrf_gpio_pin_toggle(LED_4);
        NRF_LOG_INFO("GOT WRITE ON: %d",*p_evt_write->data);
        if(*p_evt_write->data == 0x01)
        {
            nrf_gpio_pin_clear(LED_3);
        }
        else if(*p_evt_write->data == 0x02)
        {
            nrf_gpio_pin_set(LED_3);
        }
        else
        {
          //Do nothing
        }
    }
    // Check if the Custom value CCCD is written to and that the value is the appropriate length, i.e 2 bytes.
    if ((p_evt_write->handle == p_cus->custom_value_handles.cccd_handle) && (p_evt_write->len == 2))
    {
        // CCCD written, call application event handler
        if (p_cus->evt_handler != NULL)
        {
            ble_cus_evt_t evt;
            if (ble_srv_is_notification_enabled(p_evt_write->data))
            {
                evt.evt_type = BLE_CUS_EVT_NOTIFICATION_ENABLED;
            }
            else
            {
                evt.evt_type = BLE_CUS_EVT_NOTIFICATION_DISABLED;
            }
            // Call the application event handler.
            p_cus->evt_handler(p_cus, &evt);
        }
    }
}

My files -devzone.nordicsemi.com/.../1070.ble_5F00_cus.c devzone.nordicsemi.com/.../2068.ble_5F00_cus.h

devzone.nordicsemi.com/.../257070.sdk_5F00_config.h

devzone.nordicsemi.com/.../53767.main.c

RE: Bluetooth disconnects when notification enabled

Edvin — Tue, 17 Sep 2019 15:05:14 GMT

did you define DEBUG in your preprocessor defines? If you are not sure how to do it, let me know what compiler/IDE you are using, and I can help you. Segger Embedded Studio? Keil? something else?

When you define DEBUG it should tell you what the call to ble_cus_custom_value_update() returned, which is useful information, and not just that it returned != 0

RE: Bluetooth disconnects when notification enabled

bscdb — Tue, 17 Sep 2019 14:38:33 GMT

Its failing in ble_cus_custom_value_update() with fatal error.

RE: Bluetooth disconnects when notification enabled

Edvin — Tue, 17 Sep 2019 14:15:18 GMT

Hello,

Can you try to define DEBUG in your preprocessor defines, and monitor the log on the nRF? What does it say when you try to enable notifications?

Best regards,

Edvin