LoraMac. Adaptive data rate - how to swich on it?

Hi everyone!

I have stm32L072 chip and sx1272 lorachip.

I had developed a simple end-node device with stm32 lrwan library and endnode example for nucleo board.

Developed by Atollic True Studio.

Versions is: MAC_VERSION= 04.04.02.00 and STM32CubeExpansion_LRWAN_V1.3.1

options that i had used to:

LORAWAN_ADR_ON - true;
Global define REGION_EU868;
server's prefer DR is 5 (SF7);

Questions:

why uplink from device is always SF12? I think that the datarate should change itself or am I wrong?
how to make it "true" ADR?

I hear it usually takes about 20 messages before TTN starts sending ADR messages.

  1. where can i read this?
  2. what is TTN? The Things Network?

In the documentation: https://www.thethingsnetwork.org/docs/lorawan/adaptive-data-rate.html

TTN is indeed The Things Network

What I see with my node (ESP32+SX1276) and a Things Indoor gateway, is that an SF12 message (with plenty of RSSI/SNR margin) from the node is usually immediately responded to by an ADR command from the network to lower the SF (increase the rate) of the node.

A reason why ADR might not work, is that the node uses the wrong downlink parameters.
In particular the “dn2dr” downlink data rate might be configured incorrectly.
When you use OTAA, the node is told what the configured rate is and ADR should work automagically.
When you use ABP, you need to manually configure it. TTN uses SF9.