How to use mDot 868 connect to TTN？

[Xiaotian Fei]

Hi，
I’m trying use mDot 868 connect to TTN in public network. When I type this:

    mDot* dot;
   
    // get a mDot handle
    dot = mDot::getInstance();
    dot->resetConfig();

    dot->setJoinMode(mDot::AUTO_OTA);
    dot->setPublicNetwork(true);
    dot->setFrequencyBand(FB_868);
    dot->setNetworkId(app_eui);
    dot->setNetworkKey(app_key);

dot->setFrequencyBand(FB_868); this line can not pass the compile process.
So, how can I choice the 868 frequency for mDot?
Thanks！

[Mike Fiore]

Hi Xiaotian,

The mDots are configured at the factory for either the 915 band and then that configuration is locked in.

It isn’t possible to change the frequency band with the mDot library.

Cheers,

Mike

[Andrew Lindsay]

You shouldnt need to set the band. Using TTN works.
Example application is at https://developer.mbed.org/teams/Thing-Innovations/code/mDot_TTN_OTAA_Node/

Andrew

[Xiaotian Fei]

Thanks guys, I will try it.

[Xiaotian Fei]

Hi, Mike
I compile following code in the mbed online compiler, libmDot version is 14, mbed lib version is 119, mbed-rtos lib is 111.
When I download the bin file into mDot 868， the program stop at：“mDot* dot = mDot::getInstance()”.
When using the mDot 915 the programming can pass this line.

Can you help me with this problem, thanks.

#include "mbed.h"
#include "mDot.h"
#include "MTSLog.h"
#include "MTSText.h"
#include <string>
#include <vector>

using namespace mts;

#define MIN(a,b) (((a)<(b))?(a):(b))
#define MAX(a,b) (((a)>(b))?(a):(b))

// AppEUI
uint8_t AppEUI[8] = { 0x70, 0xB3, 0xD5, 0x7E, 0xD0, 0x00, 0x06, 0x56 };
// AppKey
uint8_t AppKey[16] = { 0x7F, 0xA6, 0xF7, 0x50, 0x9F, 0xE5, 0x92, 0x28, 0xD5, 0xF8, 0x79, 0xC3, 0xAD, 0x39, 0x3E, 0xD9 };

#define LORA_SF mDot::DR5
#define LORA_ACK 0
#define LORA_TXPOWER 14

Serial pc(XBEE_DOUT,XBEE_DIN);//tx, rx
 

int main() {
    int32_t ret;
    std::vector<uint8_t> send_data;
    std::vector<uint8_t> recv_data;
    std::vector<uint8_t> nwkId;
    std::vector<uint8_t> nwkKey;

    float temperature = 28.7;
   
    pc.baud(115200);
    pc.printf("TTN OTAA mDot LoRa sensor    \n\r");

    // get a mDot handle
    //
    //dot->setLogLevel(MTSLog::TRACE_LEVEL);

    pc.printf("Checking Config   ");
    // reset to default config so we know what state we're in
    mDot* dot = mDot::getInstance();
    
    pc.printf("Resetting Config    ");

    dot->resetConfig();
    
    uint8_t *it = AppEUI;
    for (uint8_t i = 0; i<8; i++)
        nwkId.push_back((uint8_t) *it++);
    
    it = AppKey;
    for (uint8_t i = 0; i<16; i++)
        nwkKey.push_back((uint8_t) *it++);

/*****************  Config mDot *****************/

    // Set Spreading Factor, higher is lower data rate, smaller packets but longer range
    // Lower is higher data rate, larger packets and shorter range.
    pc.printf("Set SF\n\r");
    if((ret = dot->setTxDataRate( LORA_SF )) != mDot::MDOT_OK) {
        logError("Failed to set SF %d:%s", ret, mDot::getReturnCodeString(ret).c_str());
    }

    pc.printf("Set TxPower\n\r");
    if((ret = dot->setTxPower( LORA_TXPOWER )) != mDot::MDOT_OK) {
        logError("Failed to set Tx Power %d:%s", ret, mDot::getReturnCodeString(ret).c_str());
    }

    pc.printf("Set Public mode\n\r");
    if((ret = dot->setPublicNetwork(true)) != mDot::MDOT_OK) {
        logError("failed to set Public Mode %d:%s", ret, mDot::getReturnCodeString(ret).c_str());
    }

    pc.printf("Set AUTO_OTA Join mode\n\r");
    if((ret = dot->setJoinMode(mDot::AUTO_OTA)) != mDot::MDOT_OK) {
        logError("Failed to set AUTO_OTA Join Mode %d:%s", ret, mDot::getReturnCodeString(ret).c_str());
    }

    pc.printf("Set Ack\n\r");
    // 1 retries on Ack, 0 to disable
    if((ret = dot->setAck( LORA_ACK)) != mDot::MDOT_OK) {
        logError("Failed to set Ack %d:%s", ret, mDot::getReturnCodeString(ret).c_str());
    }
    pc.printf("Set Network Id\n\r");
    if ((ret = dot->setNetworkId(nwkId)) != mDot::MDOT_OK) {
        logError("Failed to set Network Id %d:%s", ret, mDot::getReturnCodeString(ret).c_str());
    }
    pc.printf("Set Network Key\n\r");
    if ((ret = dot->setNetworkKey(nwkKey)) != mDot::MDOT_OK) {
        logError("Failed to set Network Id %d:%s", ret, mDot::getReturnCodeString(ret).c_str());
    }

    pc.printf("Saving Config\n\r");
    // Save config
    if (! dot->saveConfig()) {
        logError("failed to save configuration");
    }
/*****************  print mDot configs *****************/
    pc.printf("Device ID {");
    std::vector<uint8_t> deviceId;
    deviceId = dot->getDeviceId();
    for (std::vector<uint8_t>::iterator it = deviceId.begin() ; it != deviceId.end(); ++it) {
        pc.printf("0x%2.2X",*it );
        pc.printf("%s", it != (deviceId.end() -1 ) ? ", " : " " );
    }
    pc.printf("}\r\n");

    std::vector<uint8_t> netId;
    pc.printf("Network Id/App EUI {");
    netId = dot->getNetworkId();
    for (std::vector<uint8_t>::iterator it = netId.begin() ; it != netId.end(); ++it) {
        pc.printf("0x%2.2X", *it );
        pc.printf("%s", it != (netId.end() -1 ) ? ", " : " " );
    }
    pc.printf("}\r\n");

    std::vector<uint8_t> netKey;
    pc.printf("Network Key/App Key {");
    netKey = dot->getNetworkKey();
    for (std::vector<uint8_t>::iterator it = netKey.begin() ; it != netKey.end(); ++it) {
        pc.printf("0x%2.2X", *it );
        pc.printf("%s", it != (netKey.end() -1 ) ? ", " : " " );
    }
    pc.printf("}\r\n");
/***************** connect *****************/
    pc.printf("Joining Network\n\r");

    while ((ret = dot->joinNetwork()) != mDot::MDOT_OK) {
        logError("failed to join network [%d][%s]", ret, mDot::getReturnCodeString(ret).c_str());
        wait_ms(dot->getNextTxMs() + 1);
    }

    logInfo("Joined Network");
/***************** send data *****************/
    char dataBuf[50];
    while( 1 ) {
        temperature = 30.3;
        sprintf(dataBuf, "{\"t\":%3.1f}", temperature );
        pc.printf("%s\n\r",dataBuf);
        send_data.clear();
        // probably not the most efficent way to do this
        for( int i=0; i< strlen(dataBuf); i++ ) {
            send_data.push_back( dataBuf[i] );
        }

        if ((ret = dot->send(send_data)) != mDot::MDOT_OK) {
             logError("failed to send: [%d][%s]", ret, mDot::getReturnCodeString(ret).c_str());
        } else {
           logInfo("send data: %s", Text::bin2hexString(send_data).c_str());
        }

        // Should  sleep here and wakeup after a set 5 minute interval.
        // in the 868 (EU) frequency band, we need to wait until another channel is available before transmitting again
        uint32_t sleep_time = std::max((uint32_t)10000, (uint32_t)dot->getNextTxMs()) / 1000;
//wait_ms(2000);
        // go to sleep and wake up automatically sleep_time seconds later
        dot->sleep(sleep_time, mDot::RTC_ALARM, false);
    }
    return 0;
}

[Mike Fiore]

Xiaotian,

I tested your app on my 868 mDot and it seemed to work fine. Here’s the debug output

TTN OTAA mDot LoRa sensor
Checking Config Resetting Config Set SF
Set TxPower
Set Public mode
Set AUTO_OTA Join mode
Set Ack
Set Network Id
Set Network Key
Saving Config
Device ID {0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x43 }
Network Id/App EUI {0x70, 0xB3, 0xD5, 0x7E, 0xD0, 0x00, 0x06, 0x56 }
Network Key/App Key {0x7F, 0xA6, 0xF7, 0x50, 0x9F, 0xE5, 0x92, 0x28, 0xD5, 0xF8, 0x79, 0xC3, 0xAD, 0x39, 0x3E, 0xD9 }
Joining Network
TTN OTAA mDot LoRa sensor
Checking Config Resetting Config Set SF
Set TxPower
Set Public mode
Set AUTO_OTA Join mode
Set Ack
Set Network Id
Set Network Key
Saving Config
Device ID {0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x43 }
Network Id/App EUI {0x70, 0xB3, 0xD5, 0x7E, 0xD0, 0x00, 0x06, 0x56 }
Network Key/App Key {0x7F, 0xA6, 0xF7, 0x50, 0x9F, 0xE5, 0x92, 0x28, 0xD5, 0xF8, 0x79, 0xC3, 0xAD, 0x39, 0x3E, 0xD9 }
Joining Network

I suggest resetting your config to factory defaults and trying again. Also make sure your serial application (for viewing debug output) is running at 115200 since your app sets the mDot’s debug port to that speed.

Cheers,

Mike

[Xiaotian Fei]

I tried the same code again, it’s working now. Maybe I did something I have forgotten.

Thanks for running this code for me.

I have send the message {“t”:30.3} to TTN LoRa Server.

Network Key

Saving Config

Device ID {0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0xB8, 0x53 }
Network Id/App EUI {0x70, 0xB3, 0xD5, 0x7E, 0xD0, 0x00, 0x06, 0x56 }
Network Key/App Key {0x7F, 0xA6, 0xF7, 0x50, 0x9F, 0xE5, 0x92, 0x28, 0xD5, 0xF8, 0x79, 0xC3, 0xAD, 0x39, 0x3E, 0xD9 }
Joining Network

{"t":30.3}

{"t":30.3}

[Mike Fiore]

Xiaotian,

Happy to help! Please let us know if you have any other issues.

Thanks for choosing MultiTech!

Cheers,

Mike

[Author]

Posts