Host Library

This Components provides the core funcionality for the Host Emulator:


Classes to provide simple Berkeley socket support for both Linux and Windows


Command line argument parsing


Initialises SPI Flash, Uart server (in Host Drivers) and LWIP networking, then enters the main task loop. This loop services LWIP plus the task and timer queues (implemented in Host ESP HAL). The Ctrl+C keypress is trapped to provide an orderly exit. If the system has become stuck in a loop or is otherwise unresponsive, subsquent Ctrl+C presses will force a process termination.

Threads and Interrupts

The emulator uses Posix threads (pthread library) to perform background processing which would probably be done in hardware or which is outside of the framework.

Ideally we’d use SCHED_FIFO to disable time-slicing and more closely resemble how interrupts work on a single-core CPU. However, this mode isn’t supported in Windows, and Linux requires priviledged access and can potentially crash the system. Best avoided, I think.

All ESP code runs at a specific interrupt level, where 0 represents regular code. When an interrupt occurs, the level is raised according to the priority of that interrupt. Until that code has finished, only interrupts of a higher priority will pre-empt it.

The set_interrupt_level function is used to ensure that threads running at different interrupt levels do not pre-empty each other, as this would introduce problems that do not exist on real hardware. The main thread is also suspended during interrupt execution.


Default: 2ms

LWIP stack is serviced via polling, this determines the interval.


Used by