ESX: Minimal Implementation of the XMODEM Protocol

ESX (Erick's SX) is a lightweight implementation of the XMODEM protocol. This project implements the sender functionality of XMODEM, inspired by the sx tool on Linux.

Features

• Sends files over serial communication using the XMODEM protocol.
• Designed to interoperate with tools like rx on Linux.

Limitations

• Send-only: Currently supports only sending files, not receiving.
• Serial-only: Works exclusively over serial connections, but it is easy to extend.
• Fixed Parameters: Serial communication settings are hardcoded.

Building the Project

1. Create a build directory:

mkdir build
cd build

2. Generate the build files with CMake:

cmake ..

3. Compile the project:

    make

Running Unit Tests

1. Ensure the project is built (see Building the Project).
2. Navigate to the build directory and execute the tests:

    cd build
    ctest

Running System Tests

Prerequisites

• Connect two serial devices to your computer (e.g., ttyUSB0 and ttyUSB1).
• Verify the devices can communicate with each other.

Setup

1. Open system_tests/my_tester.sh and modify the following:

   • Replace /path/to/file with the file you want to send.
   • Replace /dev/ttyUSB0 and /dev/ttyUSB1 with the serial devices connected to your system.

2. Run the helper script my_tester.sh

Example Workflow

Here’s an example of sending a file named example.txt:

1. Connect two serial devices: Sender: /dev/ttyUSB0 Receiver: /dev/ttyUSB1

2. Run the sender:

../build/esx --file example.txt -p /dev/ttyUSB0 &

3. Run the receiver:

stty -F /dev/ttyUSB1 115200 cs8 -cstopb -parenb rx --xmodem -vv received_file.txt < /dev/ttyUSB1 > /dev/ttyUSB1

4. Verify the file received_file.txt