Problem getting structure

Tagged: e32, esp32

This topic has 10 replies, 2 voices, and was last updated 10 months, 3 weeks ago by poe.

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31 July 2024 at 09:24 #31164

poe

Participant

Hello!
I have a transmitter that needs to transmit a structure

void Task_LoRaSender(void) {
struct LoraData {
char type[3] = "ND";
uint8_t dev_id = config.DevID;
int32_t latitude = gnss_latitude;
int32_t longitude = gnss_longitude;
int32_t altitude = gnss_altitude;
uint8_t crc8;
} lora_data;
lora_data.crc8 = get_crc_8((const char *)&lora_data, sizeof(lora_data) - sizeof(lora_data.crc8));

ResponseStatus response_status = LORA_E32.sendFixedMessage(BASE_ADDR_H, BASE_ADDR_L, BASE_RF_CHANNEL, &lora_data, sizeof(lora_data));

char buffer_navigation_data[256];
snprintf(buffer_navigation_data, sizeof(buffer_navigation_data),
"Type: %s, ID: %d | LTD: %ld, LNG: %ld, ALT: %ld | CRC: 0x%02X",
lora_data.type, lora_data.dev_id,
lora_data.latitude, lora_data.longitude, lora_data.altitude,
lora_data.crc8);
SEND_DEBUG_MSG(buffer_navigation_data);
}

In the serial port I see (Its Ok):
Type: ND, ID: 3 | LTD: 59916757, LNG: 33590709, ALT: 127690 | CRC: 0xE0
I am successfully sending data over the air.
=================================
On the receiving side my code is:

struct LoRaNavData {
char type[3];
uint8_t dev_id;
int32_t latitude;
int32_t longitude;
int32_t altitude;
uint8_t crc8;
};

void Task_LoRa(void) {
if (LORA_E32.available() > 1) {
char type[3];
ResponseContainer rs = LORA_E32.receiveInitialMessage(sizeof(type));

String type_str = rs.data;
if (type_str == "ND") {
SEND_DEBUG_MSG("Navigation Data");
ResponseStructContainer rsc = LORA_E32.receiveMessage(sizeof(LoRaNavData));
struct LoRaNavData nav_data = *(LoRaNavData *)rsc.data;

char buffer_navigation_data[256];
snprintf(buffer_navigation_data, sizeof(buffer_navigation_data),
"Type: %s, ID: %d | LTD: %ld, LNG: %ld, ALT: %ld | CRC: 0x%02X",
type_str, nav_data.dev_id,
nav_data.latitude, nav_data.longitude, nav_data.altitude,
nav_data.crc8);
SEND_DEBUG_MSG(buffer_navigation_data);
rsc.close();
} else {
Serial.println("Something Goes Wrong!");
}
}
}

In the serial port I see something like this (not what I expected):
Type: ND, ID: 54 | LTD: -1526807549, LNG: 57776641, ALT: 0 | CRC: 0x00

I did everything according to the example, the structures are the same, but I get something completely different from what I send.

How to correctly receive structures?

31 July 2024 at 09:34 #31165
Renzo Mischianti
Keymaster
Hi Poe,
try to pass
```
char type[3] = "NDX";
```
and give us feedback.
Bye Renzo
31 July 2024 at 09:39 #31166
poe
Participant
On the sender’s side?
Compilation error: initializer-string for ‘char [3]’ is too long [-fpermissive]

31 July 2024 at 09:47 #31167

Renzo Mischianti

Keymaster

Hi,
ahh! Yes, the Terminator character.
It’s strange. Try to add this.


#pragma pack(push, 1)
struct LoRaNavData {
    char type[3];
    uint8_t dev_id;
    int32_t latitude;
    int32_t longitude;
    int32_t altitude;
    uint8_t crc8;
};
#pragma pack(pop)

Bye RM

31 July 2024 at 10:07 #31168

poe

Participant

Not working
My sender

    struct LoraData {
      char type[3] = "ND";                           // Тип структуры (навигационные данные)
      uint8_t dev_id = config.DevID;                 // ID Устройства
      int32_t latitude = gnss_latitude;              // Широта (миллионные доли градуса)
      int32_t longitude = gnss_longitude;            // Долгота (миллионные доли градуса)
      int32_t altitude = gnss_altitude;              // Высота (миллиметр)
      int32_t speed = gnss_speed;                    // Скорость
      int32_t course = gnss_course;                  // Курс (тысячные доли градуса по часовой стрелке от севера)
      uint8_t num_satellites = gnss_num_satellites;  // Количество видимых спутников (штук)
      uint8_t hdop = gnss_hdop;                      // Точность позиционирования (десятые доли, 11 соответствует 1.1)
      uint16_t sdeg = servo_deg;                     // Текущий угол серво машинки
      uint8_t crc8;                                  // Контрольная сумма структуры
    } lora_data;
    lora_data.crc8 = get_crc_8((const char *)&lora_data, sizeof(lora_data) - sizeof(lora_data.crc8));

    char buffer_navigation_data[256];
    snprintf(buffer_navigation_data, sizeof(buffer_navigation_data),
             "Type: %s, ID: %d | LTD: %ld, LNG: %ld, ALT: %ld | SPD: %ld, CRS: %ld | SATs: %d, HDOP: %d, SDeg: %d | CRC: 0x%02X",
             lora_data.type, lora_data.dev_id,
             lora_data.latitude, lora_data.longitude, lora_data.altitude,
             lora_data.speed, lora_data.course,
             lora_data.num_satellites, lora_data.hdop, lora_data.sdeg,
             lora_data.crc8);
    SEND_DEBUG_MSG(buffer_navigation_data);

    /* Отправляем пакет */
    ResponseStatus response_status = LORA_E32.sendFixedMessage(BASE_ADDR_H, BASE_ADDR_L, BASE_RF_CHANNEL, &lora_data, sizeof(LoraData));

Serial Out:
Debug Sensor: Type: ND, ID: 1 | LTD: 53916881, LNG: 27590083, ALT: 220450 | SPD: 0, CRS: 199210 | SATs: 8, HDOP: 16, SDeg: 0 | CRC: 0xE9

My receiver

/* Структура навигационных данных */
#pragma pack(push, 1)
struct NavData {
  char type[3];            // Тип структуры (навигационные данные)
  uint8_t dev_id;          // ID Устройства
  int32_t latitude;        // Широта (миллионные доли градуса)
  int32_t longitude;       // Долгота (миллионные доли градуса)
  int32_t altitude;        // Высота (миллиметр)
  int32_t speed;           // Скорость
  int32_t course;          // Курс (тысячные доли градуса по часовой стрелке от севера)
  uint8_t num_satellites;  // Количество видимых спутников (штук)
  uint8_t hdop;            // Точность позиционирования (десятые доли, 11 соответствует 1.1)
  uint16_t sdeg;           // Текущий угол серво машинки
  uint8_t crc8;            // Контрольная сумма структуры
};
#pragma pack(pop)

void Task_LoRa(void) {
  if (LORA_E32.available() > 1) {
    char type[3];
    ResponseContainer rs = LORA_E32.receiveInitialMessage(sizeof(type));

    /* Извлекаем тип пакета */
    String type_str = rs.data;
    if (type_str == "ND") {

      ResponseStructContainer rsc = LORA_E32.receiveMessage(sizeof(NavData));
      struct NavData lora_data = *(NavData *)rsc.data;

      char buffer_navigation_data[256];
      snprintf(buffer_navigation_data, sizeof(buffer_navigation_data),
               "Type: %s, ID: %d | LTD: %ld, LNG: %ld, ALT: %ld | SPD: %ld, CRS: %ld | SATs: %d, HDOP: %d, SDeg: %d | CRC: 0x%02X",
               type_str, lora_data.dev_id,
               lora_data.latitude, lora_data.longitude, lora_data.altitude,
               lora_data.speed, lora_data.course,
               lora_data.num_satellites, lora_data.hdop, lora_data.sdeg,
               lora_data.crc8);
      SEND_DEBUG_MSG(buffer_navigation_data);

      rsc.close();
    } else {
      Serial.println("Something Goes Wrong!");
    }
  }
}

Serial Out:
Debug Base: Type: ND, ID: 54 | LTD: -1526879741, LNG: 56181761, ALT: 0 | SPD: 88983040, CRS: 1116160 | SATs: 0, HDOP: 240, SDeg: 1550 | CRC: 0x00

I receive something completely different from what I sent.

31 July 2024 at 10:14 #31169
Renzo Mischianti
Keymaster
But do you use the same MCU for the sender and receiver?
31 July 2024 at 10:17 #31170
Renzo Mischianti
Keymaster
Aaah, no, wait, you read the first 3 bytes, then you try to reread the first 3 bytes again.
You must create a structure for the remaining data.

Check this article that explains how to manage the initial message.

Ebyte LoRa E32 device for Arduino, esp32 or esp8266: power saving and sending structured data – Part 5

Bye RM
31 July 2024 at 10:20 #31171
poe
Participant
I have two ESP32 modules and two LoRa E32-443T33D.
One set sends data (structure).
The second set receive data.

I output a formatted string with the values in the structure to the console.

Both structures are the same (transmitter and receiver).
The types of variables in the structure are also the same.
For example, I send dev_id = 1, and receive 54.

Sender
Debug Sensor: Type: ND, ID: 1 | LTD: 53916832, LNG: 27590070, ALT: 220810 | SPD: 0, CRS: 199210 | SATs: 8, HDOP: 16, SDeg: 0 | CRC: 0x89
Reciver
Debug Base: Type: ND, ID: 54 | LTD: -1526821373, LNG: 53004801, ALT: 0 | SPD: 50997760, CRS: 919552 | SATs: 0, HDOP: 197, SDeg: 0 | CRC: 0x00
- This reply was modified 10 months, 3 weeks ago by poe.
31 July 2024 at 10:24 #31173
Renzo Mischianti
Keymaster
The structure can’t be the same if you read the first 3 bytes.

Check the last sketch in the link I posted before.

Bye RM
31 July 2024 at 10:36 #31174
poe
Participant
Yes, it worked!
Thank you!

31 July 2024 at 13:12 #31176

poe

Participant

Another question arose about calculating the checksum of the structure…
In the transmitter, I form a static structure (for testing) and send it.

#pragma pack(push, 1)
    struct LoraData {
      char type[3] = "ND";         // Тип структуры (навигационные данные)
      uint8_t dev_id = 1;          // ID Устройства
      int32_t latitude = 2;        // Широта (миллионные доли градуса)
      int32_t longitude = 3;       // Долгота (миллионные доли градуса)
      int32_t altitude = 4;        // Высота (миллиметр)
      int32_t speed = 5;           // Скорость
      int32_t course = 6;          // Курс (тысячные доли градуса по часовой стрелке от севера)
      uint8_t num_satellites = 7;  // Количество видимых спутников (штук)
      uint8_t hdop = 8;            // Точность позиционирования (десятые доли, 11 соответствует 1.1)
      uint16_t sdeg = 9;           // Текущий угол серво машинки
      uint8_t crc8;                // Контрольная сумма структуры
    } lora_data;
#pragma pack(pop)
    lora_data.crc8 = get_crc_8((const char *)&lora_data, sizeof(lora_data) - sizeof(lora_data.type) - sizeof(lora_data.crc8));

    ResponseStatus response_status = LORA_E32.sendFixedMessage(BASE_ADDR_H, BASE_ADDR_L, BASE_RF_CHANNEL, &lora_data, sizeof(LoraData));

The checksum is 0x88 (without the type and crc8 fields)

Receiver code

void Task_LoRa(void) {
  if (LORA_E32.available() > 1) {
    /* Извлекаем тип пакета */
    char type[3];
    ResponseContainer rs = LORA_E32.receiveInitialMessage(sizeof(type));
    String type_str = rs.data;

    if (type_str == "ND") {
      /* Пакет с навигационными данными */
      /* Создаем структуру с точным количеством выделенной памяти */
#pragma pack(push, 1)
      struct NavData {
        uint8_t dev_id;          // ID Устройства
        int32_t latitude;        // Широта (миллионные доли градуса)
        int32_t longitude;       // Долгота (миллионные доли градуса)
        int32_t altitude;        // Высота (миллиметр)
        int32_t speed;           // Скорость
        int32_t course;          // Курс (тысячные доли градуса по часовой стрелке от севера)
        uint8_t num_satellites;  // Количество видимых спутников (штук)
        uint8_t hdop;            // Точность позиционирования (десятые доли, 11 соответствует 1.1)
        uint16_t sdeg;           // Текущий угол серво машинки
        uint8_t crc8;            // Контрольная сумма структуры
      } nav_data;
#pragma pack(pop)
      ResponseStructContainer rsc = LORA_E32.receiveMessage(sizeof(NavData));
      nav_data = *(NavData *)rsc.data;

      /* Проверяем контрольную сумму */
      uint8_t crc8_calc = get_crc_8((const char *)&nav_data, sizeof(nav_data) - sizeof(nav_data.crc8));
      char buffer_crc[256];
      snprintf(buffer_crc, sizeof(buffer_crc),
               "ID: %d | Rem CRC8: 0x%02X | Cal CRC8: 0x%02X",
               nav_data.dev_id, nav_data.crc8, crc8_calc);
      SEND_DEBUG_MSG(buffer_crc);
      if (crc8_calc != nav_data.crc8) {
        SEND_DEBUG_MSG("ER! CRC8 Navigation Data");
        rsc.close();
        return;
      }

      rsc.close();
    } else {
      Serial.println("Something Goes Wrong!");
    }
  }
}

But the checksum is 0x04 (without crc8 fields)
I use receiveInitialMessage.
What could be the problem with the checksum calculation?
The calculation function is the same on both sides.

This reply was modified 10 months, 3 weeks ago by poe.

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Problem getting structure

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