Multilink + NUS data reception problem

Question

Hi everyone, 
 I'm working on a project where I need to send sensor data from multiple sources to a PC. So, I'm using multiple SparkFun Pro nRF52840 Mini board (Peripherals) to acquire data from the sensor and send them over BLE. I have a nRF52840 Dongle (Central) who receive the data from the SparkFun boards and send them on serial usb to a computer. SparkFun boards send data every 1 ms. 
 The problem is when I receive data on the computer, it's like 10 data set from one board, then 10 data set from another etc. This is what it looks like when I receive the data from 3 peripheral boards and then send them over serial USB with the Dongle : 
 
 I'd like to receive 1 data set from each board everytime. But I don't really know what I need to change for that to happen. 
 The Dongle is programed with the ble_app_uart_c example + USB CDC ACM and multilink functions. The SparkFun Pro nRF52840 boards are programed with thr ble_app_uart example + SAADC functions. 
 Thanks for your help in advance, 
 Jean

Håkon · Accepted Answer

Hi, Good, it works OK when transmitting more seldom. 
 I am not sure how you do things in your code. However, a few things worth mentioning after discussing with my colleagues. 
 The minimum connection interval in BLE is 7.5 ms, per link. 
 It is possible to to decide how must time is set aside for each link on each connection interval NRF_SDH_BLE_GAP_EVENT_LENGTH - The time set aside for this connection on every connection interval in 1.25 ms units. 
 It is possible to use the Enhanced Shockburst protocol in applications where shorted connection intervals are needed.

Multilink + NUS data reception problem

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