Central receiving more than 23 bytes as a notification

[DavidC]

Hello community,

I am working in a central device with SDK 13 v. 4, PCA10400 (NRF52832) and SD 132 and one task is to receive 30 bytes from a sensors as a notifcation, but unfortunally I dont get anything, the MTU is already set up in ble_stack_init() as the following:

 #define NRF_BLE_MAX_MTU_SIZE    34

// Configure the MTU
memset(&ble_cfg, 0, sizeof(ble_cfg));
ble_cfg.conn_cfg.conn_cfg_tag = CONN_CFG_TAG;
ble_cfg.conn_cfg.params.gatt_conn_cfg.att_mtu = NRF_BLE_MAX_MTU_SIZE;
err_code = sd_ble_cfg_set(BLE_CONN_CFG_GATT, &ble_cfg, ram_start);

What else should the programm have in order to receive the 30 bytes from the sensor?

Regards,

David Caraveo

[DavidC]

for readind using cypress

Source: Destination Protocol length Info Master Slave ATT 33 Rcvd Read Request, Handle: 0x0037 Slave Master ATT 57 Rcvd Read Response

[DavidC]

I've another question, there is a way to activate the DLE using 'ble_gap_opt_ext_len_t' and using "rxtx_max_pdu_payload_size = 33" but where this code should be? Before the connection is stablish or when the ble stack is starting?

[Bjørn Kvaale]

Hi DavidC. Sorry for the delayed response. Regarding your code above, you need to look at the GATT library in SDK 13 instead of MTU. See this link for details. Also, take a look at this function in the main.c file of the ble_app_uart example under the ble_peripheral folder. Try that instead of using the sniffer. Hope that helps!

void gatt_init(void) {
ret_code_t err_code;
err_code = nrf_ble_gatt_init(&m_gatt, gatt_evt_handler);
APP_ERROR_CHECK(err_code);

err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, 64);
APP_ERROR_CHECK(err_code); }