Arduino LMIC "OP_TXRXPEND, not sending" error in serial monitor (AS923 default)

End Devices (Nodes) LMIC
1

Hello developers,

I am using Arduino pro mini and RA-01H containing SX1276 to develop a LoRa node device. The library I am using is MCCI Arduino Lora WAN library (latest version). I successfully connected the node with the TTN and sent a payload “Hello” to the server. But the communication stopped after 1/2 successful transmission and there is an error “OP_TXRXPEND, not sending” in the serial monitor.

On the TTN side, the LORAWAN setting parameters for the node are given below

Frequency plan > ASIA 920-923 Mhz
Lorawan version >LoraWan Specification 1.0.2
Regional Parameters Version > RP001 Regional Parameters 1.0.2 revision B

my payload is simple “Hello”
I am using OTAA from the example.
my TX interval is 238 s
My Pin configuration that follows the code is given below:

SX1276----Arduino pro mini
NSS> 10
RST> 9
DIO0> 2
DIO1> 3
DIO2> LMIC_UNUSED_PIN

This is the output of the serial monitor:

Starting
Packet queued
2926: EV_JOINING
331672: EV_TXSTART
696245: EV_JOINED
netid: 55
devaddr: 6E9B539F
AppSKey: 4E-CD-43-AA-7C-4A-2A-83-90-D8-A0-D7-46-7F-10-CE
NwkSKey: 0D-5F-AA-5F-89-A5-82-3A-94-53-0F-6D-9E-7E-51-09
703499: EV_TXSTART
808562: EV_TXCOMPLETE (includes waiting for RX windows)
2763586: EV_TXSTART
OP_TXRXPEND, not sending

I entered lorabase.h and saw the Spreading Factor details for AS923 which is shown below

MicrosoftTeams-image (2)

How to get rid of “OP_TXRXPEND, not sending” this issue ?

2

Let start with ‘Hello’, LoRaWAN is not suited to send plain text, it is geared to sending encoded sensor data https://www.thethingsnetwork.org/docs/devices/bytes/

How far is your node from the gateway?
What do you see in TTN console (your gateway and application)?

And if you read the thread you also posted on, have you tried any of the advise?

EDIT - seems like you are copy and past the same thread - If you are remember we are volunteers to help you, double posting don’t help to solve the issue

3

Do you get a warning when compiling the basic OTAA sketch provided with that library ?

I get,for AS923;

Sketch uses 24614 bytes (80%) of program storage space. Maximum is 30720 bytes.
Global variables use 1557 bytes (76%) of dynamic memory, leaving 491 bytes for local variables. Maximum is 2048 bytes.
Low memory available, stability problems may occur.

So who knows if its going work …