ble_uart demo throughput is very slow

[Nomados]

Hello Nordic,

I am using the BL600 third-party module and SDK 10. I was able to modify and compile project with GCC at examples\ble_peripheral\ble_app_uart\ for s110. It works nice, but the transfer speed is very low (around 500 Bytes/s). When I send a big chunk of data via UART, the module sometimes just hangs up. Definitely this example is not suitable for production. I have read all topics with descriptions about increasing the speed, but w/o success. Maybe Nordic can provide some good example for handling big amounts of data via BLE UART? Maybe with results of transfer speed for some evaluation board...

[Nomados]

I have added the BLE_GAP_EVT_CONN_PARAM_UPDATE event handler and got these results: Max interval 11 Min interval 9 So, it turned out that the Android OS agreed to decrease these intervals. I carefully measured the transfer rate and it was around 1Kbyte/s or slightly less. Maybe I should consider migration to Bluetooth 4.2 HW, which allows bigger packet size? Having 1Kb/s today sounds ridiculous nowadays :)

[Petter Myhre]

When you get the BLE_GAP_EVT_CONN_PARAM_UPDATE event the max and min should be equal, could you check again? The limitation is on the smart phone, so switching peripheral hardware wouldn't really help.

[Nomados]

They are different... I just have extended the case expression of on_ble_evt(...) function

  case BLE_GAP_EVT_CONN_PARAM_UPDATE:
      printf("Max interval %d\n",  p_ble_evt->evt.gap_evt.params.connected.conn_params.max_conn_interval);
      printf("Min interval %d\n",  p_ble_evt->evt.gap_evt.params.connected.conn_params.min_conn_interval);
      break;

[Petter Myhre]

Use:

p_ble_evt->evt.gap_evt.params.conn_param_update.conn_params.max_conn_interval
p_ble_evt->evt.gap_evt.params.conn_param_update.conn_params.min_conn_interval

[Nomados]

I got 14 and 9 for this. They are still different