Uplink invoked by downlink

End Devices (Nodes)
1

Hello,

I’m a newbie in Lora & LoraWan, so my question is probably stupid.

I have a Heltec Cubecell AB02A node connected to TTN via Dragino LPS8. The connection works fine for both uplink and downlink.

My problem is, that I want to send an uplink based on a downlink.

But my program is still stuck in a sleep state when I comment LoRaWAN.send() part (line 139).

I’m trying to send the transaction id via downlink and then send sensor data tagged with that transition via uplink.

Can somebody help me found a problem?

Thx

2

Of the device is sleeping it is a Class A nodes.
Class A nodes only receive downlink directly after sending uplinks.

Smash that learn button.

3

I’m using Class C.
The sleeping switch case is directly in the loop, so that should be the same for Class A and Class C I think.

My opinion is, that after the invocation of the downlink data handler is device reconfigured to Tx mode and I need to configure it back to Rx mode.

4

What messages are sent to the network before sleeping?
Have looked through the heltec forum?

5

Finally, something that works :slight_smile:

#include "LoRaWanMinimal_APP.h"
#include "Arduino.h"


#define LORA_BANDWIDTH                              0
#define LORA_SPREADING_FACTOR                       9
#define LORA_CODINGRATE                             1
#define LORA_PREAMBLE_LENGTH                        8         
#define LORA_SYMBOL_TIMEOUT                         0         
#define LORA_FIX_LENGTH_PAYLOAD_ON                  false
#define LORA_IQ_INVERSION_ON                        false


//////////////////////////////////////////////////////////////////////////////////////////////////////
//Set these OTAA parameters to match your app/node in TTN
uint8_t devEui[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
uint8_t appEui[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
uint8_t appKey[] = { 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x66, 0x01 };

uint16_t userChannelsMask[6]={ 0x00FF,0x0000,0x0000,0x0000,0x0000,0x0000 };
//////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////
// INIT SLEEP MODE
TimerEvent_t sleepTimer;
bool sleepTimerExpired;

static void wakeUp()
{
  sleepTimerExpired=true;
}

static void lowPowerSleep(uint32_t sleeptime)
{
  sleepTimerExpired=false;
  TimerInit( &sleepTimer, &wakeUp );
  TimerSetValue( &sleepTimer, sleeptime );
  TimerStart( &sleepTimer );
  //Low power handler also gets interrupted by other timers
  //So wait until our timer had expired
  while (!sleepTimerExpired) lowPowerHandler();
  TimerStop( &sleepTimer );
}
//////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////
// LOOP STUFF
typedef enum
{
  LOWPOWER,
  RX,
  TX
} States_t;

States_t state;
uint8_t counter = 0;
//////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////


void setup() {
	Serial.begin(115200);

  LoRaWAN.begin(LORAWAN_CLASS, ACTIVE_REGION);
  
  Radio.SetRxConfig(
      MODEM_LORA,LORA_BANDWIDTH, LORA_SPREADING_FACTOR, LORA_CODINGRATE, 0, 
      LORA_PREAMBLE_LENGTH, LORA_SYMBOL_TIMEOUT, LORA_FIX_LENGTH_PAYLOAD_ON,
      0, true, 0, 0, LORA_IQ_INVERSION_ON, true);

  LoRaWAN.setAdaptiveDR(true);

  while (1) {
    Serial.print("Joining... ");
    LoRaWAN.joinOTAA(appEui, appKey, devEui);
    if (!LoRaWAN.isJoined()) {
      Serial.println("JOIN FAILED! Sleeping for 30 seconds");
      lowPowerSleep(30000);
    } else {
      Serial.println("JOINED");
      LoRaWAN.send(1, 0, 1, true);
      break;
    }
  }
}

void loop()
{
  switch(state)
  {
    case TX:
       Serial.println("TX");
        counter++;
        LoRaWAN.send(1, &counter, 1, false);
        state=RX;
        break;
    case RX:
        Serial.println("RX");
        lowPowerHandler();
        break;
    default:
        Serial.printf("DEF");
        state=RX;
        break;
  }
}

void downLinkDataHandle(McpsIndication_t *mcpsIndication)
{
  Serial.printf("Received downlink: %s, RXSIZE %d, PORT %d, DATA: ",mcpsIndication->RxSlot?"RXWIN2":"RXWIN1",mcpsIndication->BufferSize,mcpsIndication->Port);
  for(uint8_t i=0;i<mcpsIndication->BufferSize;i++) {
    Serial.printf("%02X",mcpsIndication->Buffer[i]);
  }
  Serial.println();
  state = TX;
}
6

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