ARM Cortex-M3 Emulation (QEMU)

Overview

The Zephyr kernel uses the qemu_cortex_m3 board configuration to emulate the TI LM3S6965 platform running on QEMU. It provides support for an ARM Cortex-M3 CPU and the following devices:

  • Nested Vectored Interrupt Controller
  • System Tick System Clock
  • Stellaris UART

Note

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

Supported Boards

The qemu_cortex_m3 board configuration has been tested on QEMU 2.1 patched with Zephyr’s 0001-armv7m-support-basepri-primask-interrupt-locking.patch.

Supported Features

The qemu_cortex_m3 board configuration supports the following hardware features:

Interface Controller Driver/Component
NVIC on-chip nested vectored interrupt controller
Stellaris UART on-chip serial port
SYSTICK on-chip system clock

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

Interrupt Controller

Refer to the Freescale FRDM-K64F.

Note

Unlike the frdm_k64f board configuration, the qemu_cortex_m3 board configuration sets option NUM_IRQ_PRIO_BITS to ‘3’.

System Clock

The qemu_cortex_m3 board configuration uses a system clock frequency of 12 MHz.

Serial Port

The qemu_cortex_m3 board configuration uses a single serial communication channel with the CPU’s UART0.

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

Bibliography

  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)