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ARM Cortex-M0 Emulation (QEMU)

Overview

This board configuration will use QEMU to emulate the BBC Microbit (Nordic nRF51822) platform.

Qemu

Qemu (Credit: qemu.org)

This configuration provides support for an ARM Cortex-M0 CPU and these devices:

  • Nested Vectored Interrupt Controller

  • TIMER (nRF TIMER System Clock)

Note

This board configuration makes no claims about its suitability for use with an actual nRF51 Microbit hardware system, or any other hardware system.

Hardware

Supported Features

The following hardware features are supported:

Interface

Controller

Driver/Component

NVIC

on-chip

nested vectored interrupt controller

nRF UART

on-chip

serial port

nRF TIMER

on-chip

system clock

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

Devices

System Clock

This board configuration uses a system clock frequency of 1 MHz.

Serial Port

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

Known Problems or Limitations

The following platform features are unsupported:

  • 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 Synchronization Sample:

# From the root of the zephyr repository
west build -b qemu_cortex_m0 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.

Debugging

Refer to the detailed overview about Application Debugging.

Networking

References

  1. The Definitive Guide to the ARM Cortex-M0, Second Edition by Joseph Yiu (ISBN 978-0-12-803278-7)

  2. ARMv6-M Architecture Technical Reference Manual (ARM DDI 0419D 0403D ID051917)

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

  4. Cortex-M0 Revision r2p1 Technical Reference Manual (ARM DDI 0432C ID113009)

  5. Cortex-M0 Devices Generic User Guide (ARM DUI 0497A ID112109)