C/C++

Secondary develop Elastel Gateways by C/C++

Elastel gateways are built on an Open Linux system, allowing developers to create custom applications using C and C++.
All Elastel models support compiling and running native applications, and most devices come pre-installed with toolchains or support cross-compilation.

Typical use cases like:

• High-performance data processing and device control
• Serial, network, and protocol communication (e.g., Modbus RTU/TCP, MQTT, TCP/UDP)
• Real-time control and edge logic processing
• Integration with low-level device drivers or GPIO access

1. Supported Models

Series	Model	Compilation Method
Industrial Raspberry Pi Series	EG500, EG410, ElastBox400	Native Compilation (built-in gcc)
ARM-based IIoT Gateway Series	EG324 (Ubuntu OS)	Native Compilation (built-in gcc)
	EG324 Lite, EC212, EC211	Cross Compilation (using toolchain)

Note

✅ The EG324 model runs Ubuntu OS with gcc pre-installed, you can compile directly on it.
✅ EG324 Lite, EC212, and EC211 series do not include a compilation environment and require cross-compiling on a PC before uploading to the gateway.

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2. Cross-Compilation Environment Setup

The below example uses "admin" user on Ubuntu 20.04 PC to setup the cross-compilation environment for EG324 Lite:

1. Contact with Elastel support team to download the toolchain, and extract to /home/admin on your Ubuntu PC:

   tar -xzvf eg324l-aarch64-none-linux-gnu.tar.gz -C /home/admin

2. Add the toolchain path to ~/.bashrc and apply:

   export PATH=$PATH:/home/admin/eg324l-aarch64-none-linux-gnu/bin
   source ~/.bashrc

3. Write a test program hello.c and compile it using the cross-compiler:

   aarch64-none-linux-gnu-gcc hello.c -o hello

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3. Programming Example: LED Control (ledtest)

The following program controls the system LED blinking via /dev/led:

#include <stdio.h>
#include <linux/types.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <errno.h>

char buf;

#define LED_ON  buf = '1'; write(fd, &buf, 1)  // Turn LED on
#define LED_OFF buf = '0'; write(fd, &buf, 1)  // Turn LED off

int main(int argc, char *argv[])
{
    int fd;

    fd = open("/dev/led", O_RDWR);
    if (fd < 0)
    {
        printf("Failed to open led device");
        exit(1);
    }

    while (1)
    {
        LED_ON;
        usleep(500000);  // Delay 500 ms
        LED_OFF;
        usleep(500000);  // Delay 500 ms
    }

    exit(0);
}

3.1. Compile command:

gcc ledtest.c -o ledtest    ## Compile on device directly

# OR

aarch64-none-linux-gnu-gcc ledtest.c -o ledtest     ## Cross Comile on PC

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3.2 Upload and run on the gateway

Method 1: Upload via Web Terminal (Check ElastPro for more details)

• Open browser at http://192.168.1.1 → System → Terminal → Upload Files

• Move the uploaded file to persistent path:

  sudo mv /tmp/terminal/ledtest /home/admin/

Method 2: Using MobaXterm / Xshell

• Drag and drop via SFTP to /home/admin/

Run the program:

cd /home/admin
chmod +x ledtest
./ledtest

The LED will blink every 0.5 seconds, indicating successful control.

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4. Recommendations Practices

• Use built-in interfaces (e.g., serial ports, GPIO, LED) for development
• Configure /etc/init.d/rcS for startup service or use crontab for scheduled runs
• Deploy programs under /home/admin to avoid temporary directories
• Add error handling and logging mechanisms for production use

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5. Appendix Tables

EG324 Peripheral Resource	Device Interface Name
COM1	/dev/ttyAMA0
COM2	/dev/ttyAMA1
COM3	/dev/ttyAMA2
COM4	/dev/ttyAMA3
SYS LED Indicator	/dev/led
SYS2 LED Indicator	/dev/led2
Buzzer	/dev/buzzer
Ethernet Port 1	eth0
Ethernet Port 2	eth1

Note

For other models, please contact Elastel support or refer to models hardware manuals for Peripheral Interface tables.

• Official Website: https://www.elastel.com
• Support Email: support@elastel.com

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