2x Pico 2W RP2350 and Waveshare SX1262 (LoRa P2P Chat)

[qubit999]

Hi,

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EDIT: Full fixed code is here (Arduino Core): https://github.com/qubit999/pico-p2p-lora-chat-cpp

Same code using Pico SDK: I ported my code to picosdk as well: https://github.com/qubit999/pico-p2p-lora-chat-cpp-picosdk

################################################################

I was able to set up RadioLib to send and receive messages but the messages look like this:

[CORE1] Received: J�=�j7���{����s�U��a�m�zY�w�B��&ݼ���Y�E�v����
��������"i� ).��9���Y#.:�
[CORE1] Message: J�=�j7���{����s�U��a�m�zY�w�B��&ݼ���Y�E�v����
��������"i� ).��9���Y#.:�
[CORE1] RSSI: -109.500

or something like this:

[CORE1] Received: J�=�j2�Ԇ{����ӅU���m�k)�w��B��ٽ���Y�e�v����
��������� i�    .��9���y!.9�1��HO.�t�*�7q3�1����
                                                9��8=��4b��N+�XP�Ӷ���"@�9KcY[�7����������2[��,[Π��l���#9éAR���J�\Ǧl�>���      ��*�
   [1���@$�q�
[CORE1] Message: J�=�j2�Ԇ{����ӅU���m�k)�w��B��ٽ���Y�e�v����
��������� i�    .��9���y!.9�1��HO.�t�*�7q3�1����
                                                9��8=��4b��N+�XP�Ӷ���"@�9KcY[�7����������2[��,[Π��l���#9éAR���J�\Ǧl�>���      ��*�
   [1���@$�q�
[CORE1] RSSI: -77.5000

Maybe it has something to do with baudrate? Or with the distance of the picos to each other? I tried 2+ meter.

This is my code:

#include <stdio.h>
#include <iostream>
#include <string>
#include "pico/stdlib.h"
#include "hardware/spi.h"
#include "RadioLib.h"
#include "hal/RPiPico/PicoHal.h"
#include "pico/multicore.h"
#include "hardware/sync.h"

#define SPI_PORT   spi1
#define PIN_MISO   12
#define PIN_MOSI   11
#define PIN_SCK    10
#define PIN_CS     3
#define PIN_DIO1   20
#define PIN_RST    15
#define PIN_BUSY   2

// Create RadioLib Pico “HAL” driver
static PicoHal myHal(SPI_PORT, PIN_MISO, PIN_MOSI, PIN_SCK);
// Create SX1262 module object
static SX1262 radio = SX1262(new Module(&myHal, PIN_CS, PIN_DIO1, PIN_RST, PIN_BUSY));

// Declare a global mutex
static mutex_t radio_mutex;

// Receiver function for core1
static void core1_receiver() {
    for (;;) {
        mutex_enter_blocking(&radio_mutex);
        int state = radio.startReceive();
        if (state == RADIOLIB_ERR_NONE) {
            uint8_t receivedMessage[256];
            int length = sizeof(receivedMessage);
            int packet_length = radio.getPacketLength();
            float rssi = radio.getRSSI();
            int readState = radio.readData(receivedMessage, packet_length);
            if (readState == RADIOLIB_ERR_NONE) {
                std::cout << "[CORE1] Received: " << receivedMessage << std::endl;
                std::string message((char*)receivedMessage);
                std::cout << "[CORE1] Message: " << message << std::endl;
                std::cout << "[CORE1] RSSI: " << rssi << std::endl;
            } else {
                std::cout << "[CORE1] Read failed, code: " << readState << std::endl;
            }
        } else {
            std::cout << "[CORE1] Start receive failed, code: " << state << std::endl;
        }
        mutex_exit(&radio_mutex);
        sleep_ms(10); // Avoid busy looping
    }
}

bool sendMessage(const char* message) {
    mutex_enter_blocking(&radio_mutex);
    int state = radio.transmit(message);
    radio.finishTransmit();
    mutex_exit(&radio_mutex);
    return state == RADIOLIB_ERR_NONE;
}

int main() {
    stdio_init_all();
    mutex_init(&radio_mutex);

    int initState = radio.begin(868.0);

    if (initState != RADIOLIB_ERR_NONE) {
        printf("Radio init failed, code %d\n", initState);
        while (true) { /* halt */ }
    }

    // Launch receiver on core1
    multicore_launch_core1(core1_receiver);

    // Core0: Transmit loop
    while (true) {
        if (!sendMessage("Hello 12")) {
            printf("[CORE0] Send failed\n");
        }
        sleep_ms(2000); 
    }

    return 0;
}

Any ideas?

[qubit999]

I changed the code a bit, still the same:

[CORE0] Message sent!
[SX1262] Received packet!
[SX1262] Data:  j�=�j6�Ԇ{����s�T��a�m�zI��B��&ݵ���Y�e�v����
���Ѣ���"i� ).�칝��Y#.8�Q��X.�t�*�9q7�1�_5N��9��0=�W�4b��H+����Ӗ��� @�9KcIY�6����k��m$2k��
                                                                                         [��l�������A^���J�\��l�����   ��*�
                                                                                                                            [1�@d�1�(��n��A�����w� eGnK�L�oh��}:<�
[SX1262] RSSI:  -109.500 dBm
[SX1262] SNR:   -7.00000 dB
[CORE1] Start receive state: 0
[CORE0] Message sent!
[SX1262] Received packet!
[SX1262] Data:  j�=�j6�Ԇ{����s�T��a�m�zI��B��&ݵ���Y�e�v����
���Ѣ���"i� ).�칝��Y#.8�Q��X.�t�*�9q7�1�_5N��9��0=�W�4b��H+����Ӗ��� @�9KcIY�6����k��m$2k��
                                                                                         [��l�������A^���J�\��l�����   ��*�
                                                                                                                            [1�@d�1�(��n��A�����w� eGnK�L�oh��}:<�
[SX1262] RSSI:  -109.500 dBm
[SX1262] SNR:   -7.00000 dB
[CORE1] Start receive state: 0
[CORE0] Message sent!
[SX1262] Received packet!
[SX1262] Data:  j�=�j6�Ԇ{����s�T��a�m�zI��B��&ݵ���Y�e�v����
���Ѣ���"i� ).�칝��Y#.8�Q��X.�t�*�9q7�1�_5N��9��0=�W�4b��H+����Ӗ��� @�9KcIY�6����k��m$2k��
                                                                                         [��l�������A^���J�\��l�����   ��*�
                                                                                                                            [1�@d�1�(��n��A�����w� eGnK�L�oh��}:<�
[SX1262] RSSI:  -109.500 dBm
[SX1262] SNR:   -7.00000 dB
[CORE1] Start receive state: 0
[CORE0] Message sent!
[SX1262] Received packet!
[SX1262] Data:  j�=�j6�Ԇ{����s�T��a�m�zI��B��&ݵ���Y�e�v����
���Ѣ���"i� ).�칝��Y#.8�Q��X.�t�*�9q7�1�_5N��9��0=�W�4b��H+����Ӗ��� @�9KcIY�6����k��m$2k��
                                                                                         [��l�������A^���J�\��l�����   ��*�
                                                                                                                            [1�@d�1�(��n��A�����w� eGnK�L�oh��}:<�
[SX1262] RSSI:  -109.500 dBm
[SX1262] SNR:   -7.00000 dB
[CORE1] Start receive state: 0

This is the code:

#include <stdio.h>
#include <iostream>
#include <string>
#include "pico/stdlib.h"
#include "hardware/spi.h"
#include "RadioLib.h"
#include "hal/RPiPico/PicoHal.h"
#include "pico/multicore.h"
#include "hardware/sync.h"

#define SPI_PORT   spi1
#define PIN_MISO   12
#define PIN_MOSI   11
#define PIN_SCK    10
#define PIN_CS     3
#define PIN_DIO1   20
#define PIN_RST    15
#define PIN_BUSY   2

// Create RadioLib Pico “HAL” driver
static PicoHal myHal(SPI_PORT, PIN_MISO, PIN_MOSI, PIN_SCK);
// Create SX1262 module object
static SX1262 radio = SX1262(new Module(&myHal, PIN_CS, PIN_DIO1, PIN_RST, PIN_BUSY));

// Declare a global mutex
static mutex_t radio_mutex;

volatile bool receivedFlag = false;

void clearFlag() {
    receivedFlag = false;
}

void setFlag() {
    receivedFlag = true;
}

// Receiver function for core1
static void core1_receiver() {
    for (;;) {
        mutex_enter_blocking(&radio_mutex);
        int state = radio.startReceive();
        std::cout << "[CORE1] Start receive state: " << state << std::endl;
        mutex_exit(&radio_mutex);
        
        if (state == RADIOLIB_ERR_NONE) {
            while (!receivedFlag) {
                sleep_ms(10); // Avoid busy looping
            }

            mutex_enter_blocking(&radio_mutex);
            clearFlag();
            uint8_t receivedMessage[256];
            int packet_length = radio.getPacketLength();
            float rssi = radio.getRSSI();
            int readState = radio.readData(receivedMessage, 0);
            if (readState == RADIOLIB_ERR_NONE) {
                // packet was successfully received
                std::cout << "[SX1262] Received packet!" << std::endl;
                std::cout << "[SX1262] Data:\t" << receivedMessage << std::endl;
                std::cout << "[SX1262] RSSI:\t" << rssi << " dBm" << std::endl;
                std::cout << "[SX1262] SNR:\t" << radio.getSNR() << " dB" << std::endl;
            } else if (readState == RADIOLIB_ERR_CRC_MISMATCH) {
                // packet was received, but has a CRC error
                std::cout << "CRC error!" << std::endl;
            } else {
                // some other error occurred
                std::cout << "failed, code " << readState << std::endl;
            }
            mutex_exit(&radio_mutex);
        }
    }
}

bool sendMessage(const char* message) {
    mutex_enter_blocking(&radio_mutex);
    int state = radio.transmit(message);
    radio.finishTransmit();
    mutex_exit(&radio_mutex);
    return state == RADIOLIB_ERR_NONE;
}

int main() {
    stdio_init_all();
    mutex_init(&radio_mutex);

    int initState = radio.begin(868.0);

    if (initState != RADIOLIB_ERR_NONE) {
        printf("Radio init failed, code %d\n", initState);
        while (true) { /* halt */ }
    }

    radio.setDio1Action(setFlag);

    // Launch receiver on core1
    multicore_launch_core1(core1_receiver);

    // Core0: Transmit loop
    while (true) {
        if (!sendMessage("Hello 12")) {
            std::cout << "[CORE0] Failed to send message" << std::endl;
        } else {
            std::cout << "[CORE0] Message sent!" << std::endl;
        }
        myHal.delay(2000);
    }

    return 0;
}

[jgromes]

tried to adjust it like in RadioLib/examples/SX126x/PingPong

Then I suggest trying to understand that example first, ideally running it, before attempting any changes. You have missed crucial parts of the logic.

For example, the fact that startReceive will start reception. It does not block until a packet is received - so why are you trying to immediately call readData? I'm happy to help if you have a specific question, but I'm not a debugger, nor a ChatGPT-style large language model, so don't expect that I will fix your code when you throw it at me ;)

[qubit999]

Thank you in advance!

I managed to get sending and receiving fixed. So one Pico sends and the other Pico receives. So from technical side it's working.

But now I need to figure out how to do that half-duplex thingy.

[jgromes]

On SX126x, there's only one interrupt signal; the same pin is used to signal both transmission end, as well as packet being received. So (as the PingPong example shows), you have to use a single interrupt service routine to set a flag, and then decide in the main program what caused it. Calling both of these methods will just overwrite the ISR that is being called, so the code above will always just call setRXFlag

[qubit999]

Thank you sooo much! I fixed it right now. Chat works!

I will upload it to GitHub.

Fixed code: https://github.com/qubit999/pico-p2p-lora-chat-cpp

[qubit999]

I ported my code to picosdk as well: https://github.com/qubit999/pico-p2p-lora-chat-cpp-picosdk