Send struct

[spa-sam]

Can you add an example of how to send and receive a structure?

[zybernatic]

I also got the same issue about sending the packet. it seem that it stuck in this line when calling the endPacket

while((readRegister(REG_IRQ_FLAGS) & IRQ_TX_DONE_MASK) == 0);

it keep looping forever.

i use the board from heltec

and here is my sketch

`#include

include

include

// WIFI_LoRa_32 ports

// GPIO5 -- SX1278's SCK // GPIO19 -- SX1278's MISO // GPIO27 -- SX1278's MOSI // GPIO18 -- SX1278's CS // GPIO14 -- SX1278's RESET // GPIO26 -- SX1278's IRQ(Interrupt Request)

define SS 18

define RST 14

define DI0 26

define BAND 433E6 //915E6 -- 这里的模式选择中，检查一下是否可在中国实用915这个频段

int counter = 0;

void setup() { pinMode(25,OUTPUT); //Send success, LED will bright 1 second

Serial.begin(115200); while (!Serial); //If just the the basic function, must connect to a computer

SPI.begin(5,19,27,18); LoRa.setPins(SS,RST); LoRa.setTxPower(10); // Serial.println("LoRa Sender");

if (!LoRa.begin(BAND)) { Serial.println("Starting LoRa failed!"); while (1); } Serial.println("LoRa Initial OK!"); }

void loop() { Serial.print("Sending packet: "); Serial.println(counter);

// send packet LoRa.beginPacket(); LoRa.print("hello "); LoRa.print(counter); LoRa.endPacket();

counter++; digitalWrite(25, HIGH); // turn the LED on (HIGH is the voltage level) delay(1000); // wait for a second digitalWrite(25, LOW); // turn the LED off by making the voltage LOW delay(1000); // wait for a second

delay(3000); }`

[sandeepmistry]

@spa-sam you can use https://github.com/sandeepmistry/arduino-LoRa/blob/master/API.md#writing but pass in the address and length of the structure, you'll have to cast to uint8_t*.

[richardfyeo]

Hi, Just in case anyone else is still wondering about this question, as Sandeep mentions above, you can read and write using the address of the buffer/structure etc that you have filled with data.
So for the Tx you have

LoRa.beginPacket();
LoRa.write((uint8_t*)&data, sizeof(data));
LoRa.endPacket();

and for the Rx I have

int packetSize = LoRa.parsePacket ();
 if (packetSize) // Only read if there is some data to read..
  {
    LoRa.readBytes((uint8_t *)&data, packetSize);
  }

This is working fine for me using a structure containing a mix of floats, ints and bytes, although I got caught out by the different default sizes of ints on ESP32 (Rx) and the ATmega (Tx). On the ESP32 I had to explicitly define the ints in my data structure as short ints, otherwise the int values received were wrong..

[akshay0070]

if I want to send an acknowledgement back to the sender after receiving the data, how to establish an acknowledgement system. tried the above-mentioned code by Richardfyeo that is not working for me can you just explain little more

[IoTThinks]

@akshay0070 Start a new thread.