esp-protocols/esp_modem/docs/internal_desing.md

Internal design

Design decisions

• Use C++ (lambdas) wit C API
• Use exceptions (implement nothrow? possibly using assert())
• Initializes and allocates in the constructor (might throw)
• Implements different devices with template specialization
• Specific device abstraction overrides methods, but does not use virtual function dispatch (modeled as DCE<SpecificModule>)

DCE collaboration model

The diagram describes how the DCE class collaborates with DTE, PPP and the device abstraction

Terminal inheritance

Terminal is a class which can read or write data, and can handle callbacks when data are available. UART specialization is provided implementing these method using the uart driver.

CMUX terminal

The below diagram depicts the idea of using CMUX terminal mode using the CMUXedTerminal class which is a terminal (it implements the basic read/write methods) interfacing arbitrary number of virtual terminals, but at the same time it is also composed of another terminal, the real terminal, which is multiplexed.