Hi there,
I need to transmit 33995520 bytes from nrf52 peripheral device to a Windows/Android device. Currently it takes about 13 to 14 minutes to complete the data transfer with some packet drops. My connection parameters are as follows-
#define MIN_CONN_INTERVAL MSEC_TO_UNITS(7.5, UNIT_1_25_MS) /**< Minimum acceptable connection interval (0.1 seconds). */ #define MAX_CONN_INTERVAL MSEC_TO_UNITS(15, UNIT_1_25_MS) /**< Maximum acceptable connection interval (0.2 second). */ #define SLAVE_LATENCY 0 /**< Slave latency. */ #define CONN_SUP_TIMEOUT MSEC_TO_UNITS(10000, UNIT_10_MS) /**< Connection supervisory timeout (4 seconds). */
#ifndef NRF_SDH_BLE_GAP_EVENT_LENGTH #define NRF_SDH_BLE_GAP_EVENT_LENGTH 400//6 #endif #ifndef NRF_SDH_BLE_GATT_MAX_MTU_SIZE #define NRF_SDH_BLE_GATT_MAX_MTU_SIZE 230//247//35//23 #endif #ifndef NRF_SDH_BLE_GAP_DATA_LENGTH #define NRF_SDH_BLE_GAP_DATA_LENGTH 234//233//27 #endif
case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
{
NRF_LOG_DEBUG("PHY update request.");
ble_gap_phys_t const phys =
{
.rx_phys = BLE_GAP_PHY_2MBPS,
.tx_phys = BLE_GAP_PHY_2MBPS,
};
err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
APP_ERROR_CHECK(err_code);
}break;
Overall, I see ~6 packets getting dropped.
I tried to add more checks like tracking BLE_GATTS_EVT_HVN_TX_COMPLETE or looking out for NRF_SUCCESS but then I lose more data. I also tried to increase the connection interval to 50 to 100 ms, still the same result. Do you have any suggestions?
