Error enabling connection event extension in UART example

[Clonimmus74]

Hi all,

I use nRF52832 with the UART peripheral example.

I try to enable connection event extension in the device and get an error.

I use SDK V15.0.0 and Softdevice V 6.0.0

I put the following code at the end of the nrf_sdh_ble_default_cfg_set function:

    ble_opt_t  opt;
    memset(&opt, 0x00, sizeof(opt));
    opt.common_opt.conn_evt_ext.enable = 1;
    ret_code = sd_ble_opt_set(BLE_COMMON_OPT_CONN_EVT_EXT, &opt);
    APP_ERROR_CHECK(ret_code);

ret_code returns with 0x3001.

What am I doing wrong?

I'm am new to BLE and my knowledge is limited, specific detailed answers will be greatly appreciated.

Thank you

[Clonimmus74]

Thank you
What is hvn queue size and is there a limit to its size?

[dani_cvetanov]

Gents,

I have absolutely the same issue with that SDK and that chip. I have set the MTU to 244 bytes. With the default connection interval (min=20. max=75mS) I get ~700bytes/sec. When I reduce the connection interval to 15mS (min and max), then the throughput increases to 2100bytes/sec.

What are we missing? 

[Clonimmus74]

Yes, I tried it with a phone running Android 8 (Honor 9).

I also tried it with Nordic Central (same chip, using eval board PCA10040)

[dani_cvetanov]

Solved on my side! It seems that our issue is that we have our own message queue and we're waiting for the BLE_GATTS_EVT_HVN_TX_COMPLETE event in order to send the next packet. However, this limits the maximum TX packets to 1 per connection interval. We should use the HVN queue if we want to boost the throughput.

[Clonimmus74]

Can you please elaborate, as I'm extremely new to BLE, and Nordic especially....

Thanks