Large data transfer [nRF5 SDK v. 11, nRF52-DK, BLE]

RE: Large data transfer [nRF5 SDK v. 11, nRF52-DK, BLE]

Anders Strand — Tue, 14 Jun 2016 07:42:56 GMT

Who is sending the parameter update request, the central or the peripheral?. Can you attach the sniffer log to your first post?

The connection intervals in the SDK examples are set on top of main.c

#define MIN_CONN_INTERVAL                MSEC_TO_UNITS(400, UNIT_1_25_MS)           /**< Minimum acceptable connection interval (0.4 seconds). */
#define MAX_CONN_INTERVAL                MSEC_TO_UNITS(650, UNIT_1_25_MS)           /**< Maximum acceptable connection interval (0.65 second). */
#define CONN_SUP_TIMEOUT                 MSEC_TO_UNITS(4000, UNIT_10_MS)            /**< Connection supervisory timeout (4 seconds). */
#define FIRST_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(5000, APP_TIMER_PRESCALER) /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY    APP_TIMER_TICKS(30000, APP_TIMER_PRESCALER)/**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT     3                                          /**< Number of attempts before giving up the connection parameter negotiation. */

These values are from the ble_app_hrs example in SDK 11

The ble_conn_params.c module will negotiate connection parameters when gap_params_init() is called in main().

The FIRST_CONN_PARAMS_UPDATE_DELAY controls the time between connection and when the peripheral requests new connection parameters.

RE: Large data transfer [nRF5 SDK v. 11, nRF52-DK, BLE]

Pawel J — Mon, 13 Jun 2016 11:42:13 GMT

It seems you're intuition is right as there is parameters update event going on. This is what I have logged: BLE_GAP_EVT_CONN_PARAM_UPDATE_REQUEST: min_conn_interval: 320 max_conn_interval: 520 conn_sup_timeout: 400 slave_latency: 0 Have you got an idea how could I avoid that? Thank you!

RE: Large data transfer [nRF5 SDK v. 11, nRF52-DK, BLE]

Anders Strand — Fri, 10 Jun 2016 11:37:31 GMT

do you have a nRF51 you can set up as an nRF sniffer?. If not, add some printing which can tell us the connection parameters being set on EVT_CONNE and on the BLE_GAP_EVT_CONN_PARAM_UPDATE event. (Check on_conn_params_update() in ble_conn_params.c or catch the event in main.c. This sound like connection parameters being updated

RE: Large data transfer [nRF5 SDK v. 11, nRF52-DK, BLE]

Pawel J — Fri, 10 Jun 2016 09:42:24 GMT

Central device is other nRF52 DK. I am stopping the timer as I use heart_rate_meas_timeout only to initiate the data burst. Then, as in aforementioned example, I send the data in while loop to achieve the fastest transfer. Thus yes, the timers make the device send notifications in the original example, but this one is changed according to needs (I am editing the original post to attach the code).

RE: Large data transfer [nRF5 SDK v. 11, nRF52-DK, BLE]

Anders Strand — Fri, 10 Jun 2016 09:30:22 GMT

What is your central device? This will control this more than anything. Why are you stopping the timers? If i remember correctly, these are the events that make the device send notifications.

RE: Large data transfer [nRF5 SDK v. 11, nRF52-DK, BLE]

Pawel J — Thu, 09 Jun 2016 07:27:55 GMT

Those are: Minimum connection interval: 7.5ms, Maximum connection interval: 30ms Slave latency: 0 Supervision timeout: 4000ms

RE: Large data transfer [nRF5 SDK v. 11, nRF52-DK, BLE]

James Yu — Wed, 08 Jun 2016 15:57:32 GMT

What are your connection parameters?