nrf51822 BLE disconnection problem

[DragonAnger]

Hi, I'm using nrf51822 and ble_app_uart(SDK 12.3.0)

What I want to do is connect my board with nrf51822 and send data over UART

and send data to smartphone over BLE

UART data comes about 50bytes/sec

My problem is BLE connection is keep disconnected.

Actually, Hard to connect BLE at first. Sometimes do, Sometimes don't.

When it connected fortunately, It will disconnected soon.

Disconnecting time is unpredictable.

Sometimes smartphone receive data, sometimes don't.

I didn't changed sample code.

I'm new BLE, please help me..

Thanks!

void uart_event_handle(app_uart_evt_t * p_event){
static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
static uint8_t index = 0;
uint32_t       err_code;

switch (p_event->evt_type)
{
    case APP_UART_DATA_READY:
        UNUSED_VARIABLE(app_uart_get(&data_array[index]));
        index++;
        if ((data_array[index - 1] == '\r') || (index >= (BLE_NUS_MAX_DATA_LEN)))
        {
            err_code = ble_nus_string_send(&m_nus, data_array, index);
					
            if (err_code != NRF_ERROR_INVALID_STATE)
            {
                APP_ERROR_CHECK(err_code);
            }

[DragonAnger]

I found some details about this problem.

When BLE disconnected, at this code

err_code = ble_nus_string_send(&m_nus, data_array, index);

NRF_ERROR_INVALID_STATE occurs.

When it occurs, data didn't come to my android phone.

When it didn't occur, data comes to my phone fine.

Before NRF_ERROR_INVALID_STATE occurs,

app_uart_init() function in app_uart_fifo.c called couple of times

and soon BLE disconnected