zephyr/boards/x86/qemu_x86/doc/board.rst

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.. _qemu_x86:
X86 Emulation (QEMU)
####################
Overview
********
The Zephyr Kernel uses the qemu_x86 board configuration to emulate pentium-class
systems running on QEMU.
This board configuration provides support for an x86 Minute IA CPU and the
following devices:
* HPET
* Advanced Programmable Interrupt Controller (APIC)
* NS16550 UART
Hardware
********
Supported Features
==================
The qemu_x86 board configuration supports the following hardware features:
+--------------+------------+-----------------------+
| Interface | Controller | Driver/Component |
+==============+============+=======================+
| HPET | on-chip | system clock |
+--------------+------------+-----------------------+
| APIC | on-chip | interrupt controller |
+--------------+------------+-----------------------+
| NS16550 | on-chip | serial port |
| UART | | |
+--------------+------------+-----------------------+
Devices
=======
HPET System Clock Support
-------------------------
The qemu_x86 board configuration uses an HPET clock frequency of 25 MHz.
Serial Port
-----------
The qemu_x86 board configuration uses a single serial communication channel that
uses the NS16550 serial driver operating in polling mode. To override, enable
the UART_INTERRUPT_DRIVEN Kconfig option, which allows the system to be
interrupt-driven.
Known Problems or Limitations
=============================
The following platform features are unsupported:
* Isolated Memory Regions
* Serial port in Direct Memory Access (DMA) mode
* Serial Peripheral Interface (SPI) flash
* General-Purpose Input/Output (GPIO)
* Inter-Integrated Circuit (I2C)
* Ethernet
* Supervisor Mode Execution Protection (SMEP)