Abnormal slow bitrate (MTU=20). nRF52. SDK12.

[Oleg]

Good time dear Engineers!

Faced with a general Problem.

I use two nRF52 boards connection : Central <-> Peritheral. init data: MIN/MAX conn intervals = 10/30 ms

test Algorithm:

1. Write char value (19 bytes) use sd_ble_gattc_write(conn_h, &write_params);

2. Waiting for... BLE_EVT_TX_COMPLETE

3. Read char value use sd_ble_gattc_read(conn_h, char_h, 0);

4. Waiting for... BLE_GATTC_EVT_READ_RSP

Sometimes, the DELAY between 1& 2 or 3&4 reaches up to 2 seconds, but in other time all good & very fast (immediately). also, I noticed this happens periodically 'in waves'.

WHY? What parameters possible wrong ?

Thanks you!

CONN_PARAMETERS UPDATES DATA (20 ms):

LOG FILE:

[Oleg]

hi dear Petter! I attached shot with my LOG data. both CONN_PARAM are veri fast - it's 20 ms. slave latency =1. I dont understand why so slow...