This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

ARM Cortex-M3 Emulation (QEMU)


This board configuration will use QEMU to emulate the TI LM3S6965 platform.

This configuration provides support for an ARM Cortex-M3 CPU and these devices:

  • Nested Vectored Interrupt Controller

  • System Tick System Clock

  • Stellaris UART


This board configuration makes no claims about its suitability for use with an actual ti_lm3s6965 hardware system, or any other hardware system.


Supported Features

The following hardware features are supported:






nested vectored interrupt controller

Stellaris UART


serial port



system clock

The kernel currently does not support other hardware features on this platform.


System Clock

This board configuration uses a system clock frequency of 12 MHz.

Serial Port

This board configuration uses a single serial communication channel with the CPU’s UART0.

If SLIP networking is enabled (see below), an additional serial port will be used for it.

Known Problems or Limitations

The following platform features are unsupported:

  • Memory protection through optional MPU. However, using a XIP kernel effectively provides TEXT/RODATA write protection in ROM.

  • SRAM at addresses 0x1FFF0000-0x1FFFFFFF

  • Writing to the hardware’s flash memory

Programming and Debugging

Use this configuration to run basic Zephyr applications and kernel tests in the QEMU emulated environment, for example, with the Basic Synchronization sample:

# From the root of the zephyr repository
west build -b qemu_cortex_m3 samples/synchronization
west build -t run

This will build an image with the synchronization sample app, boot it using QEMU, and display the following console output:

***** BOOTING ZEPHYR OS v1.8.99 - BUILD: Jun 27 2017 13:09:26 *****
threadA: Hello World from arm!
threadB: Hello World from arm!
threadA: Hello World from arm!
threadB: Hello World from arm!
threadA: Hello World from arm!
threadB: Hello World from arm!
threadA: Hello World from arm!
threadB: Hello World from arm!
threadA: Hello World from arm!
threadB: Hello World from arm!

Exit QEMU by pressing CTRL+A x.


Refer to the detailed overview about Application Debugging.


The board supports SLIP networking over an emulated serial port (CONFIG_NET_SLIP_TAP=y). The detailed setup is described in Networking with QEMU.

It is also possible to use the QEMU built-in Ethernet adapter to connect to the host system. This is faster than using SLIP and is also the preferred way. See Networking with QEMU Ethernet for details.


  1. The Definitive Guide to the ARM Cortex-M3, Second Edition by Joseph Yiu (ISBN 978-0-12-382090-7)

  2. ARMv7-M Architecture Technical Reference Manual (ARM DDI 0403D ID021310)

  3. Procedure Call Standard for the ARM Architecture (ARM IHI 0042E, current through ABI release 2.09, 2012/11/30)

  4. Cortex-M3 Revision r2p1 Technical Reference Manual (ARM DDI 0337I ID072410)

  5. Cortex-M3 Devices Generic User Guide (ARM DUI 0052A ID121610)