Binary Communications Example Project¶

This ISCommExample project demonstrates binary communications with the
Inertial Sense Products (IMX) using the Inertial Sense SDK.

Files¶

Project Files¶

ISCommExample.cpp

SDK Files¶

Implementation¶

Step 1: Add Includes¶

// Change these include paths to the correct paths for your project
#include "ISComm.h"
#include "ISPose.h"
#include "ISUtilities.h"
#include "PortFactory.h"
#include "protocol_nmea.h"

Step 2: Initialize and open serial port¶

    // Initialize the serial port (Windows, MAC or Linux) - if using an embedded system like Arduino,
    //  you will need to handle the serial port creation, open and reads yourself.

    SerialPortFactory& spf = SerialPortFactory::getInstance();
    spf.setBaudRate(921600);
    port_handle_t port = spf.bindPort(argv[1]);

    if (port == nullptr) {
        printf("Failed to allocate port\r\n");
        return -2;
    }

    // Binding a port does not open a port.. so let's open it
    if (!portIsOpened(port) && (portOpen(port) != PORT_ERROR__NONE)) {
        printf("Failed to open port\r\n");
        return -3;
    }

Step 3: Stop any message broadcasting¶

    is_comm_stop_broadcasts_all_ports(port);

Step 4: Bind callbacks to the port¶

    // Any ISB protocol messages will call into this handler (defined above).
    is_comm_register_port_isb_handler(port, isbDataHandler);

The handler receives a p_data_t* for every successfully parsed message; data->hdr.id identifies the DID and data->ptr points at the payload struct:

int isbDataHandler(void* ctx, p_data_t* data, port_handle_t port) {
    switch (data->hdr.id)
    {
    case DID_INS_1:
        handleIns1Message((ins_1_t*)data->ptr);
        break;

    case DID_INS_2:
        handleIns2Message((ins_2_t*)data->ptr);
        break;

    case DID_GNSS1_POS:
        handleGpsMessage((gnss_pos_t*)data->ptr);
        break;

    case DID_IMU:
        handleImuMessage((imu_t*)data->ptr);
        break;

        // TODO: add other cases for other data ids that you care about
    }

    return 0;
}

Step 5: Set configuration (optional)¶

    // Set INS output Euler rotation in radians to 90 degrees roll for mounting
    float rotation[3] = { 90.0f*C_DEG2RAD_F, 0.0f, 0.0f };
    is_comm_set_data(port, DID_FLASH_CONFIG, sizeof(float) * 3, offsetof(nvm_flash_cfg_t, insRotation), rotation);

Step 6: Enable message broadcasting¶

    // Ask for INS message w/ update 40ms period (4ms source period x 10).  Set data rate to zero to disable broadcast and pull a single packet.
    is_comm_get_data(port, DID_INS_1, 0, 0, 10);

    // Ask for GPS message at period of 200ms (200ms source period x 1).  Size and offset can be left at 0 unless you want to just pull a specific field from a data set.
    is_comm_get_data(port, DID_GNSS1_POS, 0, 0, 1);

    // Ask for IMU message at period of 96ms (DID_FLASH_CONFIG.startupNavDtMs source period x 6).  This could be as high as 1000 times a second (period multiple of 1)
    is_comm_get_data(port, DID_IMU, 0, 0, 6);

Step 7: Save Persistent Messages¶

(OPTIONAL) Save currently enabled streams as persistent messages enabled after reboot.

    system_command_t cfg;
    cfg.command = SYS_CMD_SAVE_PERSISTENT_MESSAGES;
    cfg.invCommand = ~cfg.command;

    is_comm_set_data(port, DID_SYS_CMD, 0, 0, &cfg);

Step 8: Process and parse messages from the port¶

    // This should run a fairly fast rate, (1ms is typical) to avoid data from filling
    // the COMM buffer, which could lead to data drop.
    while (portIsOpened(port)) {
        is_comm_port_parse_messages(port);
        SLEEP_MS(1);
    }

Compile & Run (Linux/Mac)¶

Create build directory

cd InertialSenseSDK/ExampleProjects/ISComm
mkdir build

Run cmake from within build directory
```
cd build
cmake ..
```
Compile using make
```
make
```
If necessary, add current user to the "dialout" group in order to read and write to the USB serial communication ports:
```
sudo usermod -a -G dialout $USER
sudo usermod -a -G plugdev $USER
(reboot computer)
```
Run executable
```
./ISCommExample /dev/ttyUSB0
```

Compile & Run (Windows Powershell)¶

*Note - Install CMake for Windows natively, or install the CMake for Windows extension for Visual Studio

Create build directory

cd InertialSenseSDK/ExampleProjects/ISComm
mkdir build

Run cmake from within build directory
```
cd build
cmake ..
```
Compile using make
```
cmake --build .
```

Run executable

C:\InertialSenseSDK\ExampleProjects\ISComm\build\Release\ISCommExample.exe COM3

Summary¶

This section has covered the basic functionality you need to set up and communicate with Inertial Sense products. If this doesn't cover everything you need, feel free to reach out to us on the Inertial Sense SDK GitHub repository, and we will be happy to help.