This is the documentation for the latest (master) 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.

MHU Dual Core

Overview

An MHU (Message Handling Unit) enables software to raise interrupts to the processor cores. This sample is a simple dual-core example for a Musca A1 board that has two MHU units. This sample only test MHU0, the steps are:

  1. CPU 0 will wake up CPU 1 after initialization

  2. CPU 1 will send to CPU 0 an interrupt over MHU0

  3. CPU 0 return the same to CPU 1 when received MHU0 interrupt

  4. Test done when CPU 1 received MHU0 interrupt

Building and Running

On Musca B1

This project outputs ‘IPM MHU sample on musca_b1’ to the console. It can be built and executed on Musca B1 CPU 0 as follows:

west build -b v2m_musca_b1 samples/subsys/ipc/ipm_mhu_dual_core
west build -t run

This project outputs ‘IPM MHU sample on v2m_musca_b1_nonsecure’ to the console. It can be built and executed on Musca B1 CPU 1 as follows:

west build -b v2m_musca_b1_nonsecure samples/subsys/ipc/ipm_mhu_dual_core
west build -t run

Combine images for Musca

A third-party tool (srecord) is used to generate the Intel formatted hex image. For more information refer to the Srecord Manual.

srec_cat zephyr.bin -Binary -offset $IMAGE_OFFSET zephyr_nonsecure.bin -Binary -offset $IMAGE_NS_OFFSET -o dual_core_zephyr.hex -Intel

# This command is an example for Musca B1
srec_cat zephyr.bin -Binary -offset 0xA000000 zephyr_nonsecure.bin -Binary -offset 0xA060400 -o dual_core_zephyr.hex -Intel

Open a serial terminal (minicom, putty, etc.) and connect the board with the following settings:

  • Speed: 115200

  • Data: 8 bits

  • Parity: None

  • Stop bits: 1

Reset the board and the following message will appear on the corresponding serial port.

Sample Output

***** Booting Zephyr OS zephyr-v1.13.0-3378-g3625524 *****
IPM MHU sample on musca_a
CPU 0, get MHU0 success!
***** Booting Zephyr OS zephyr-v1.13.0-3378-g3625524 *****
IPM MHU sample on musca_a_nonsecure
CPU 1, get MHU0 success!
MHU ISR on CPU 0
MHU ISR on CPU 1
MHU Test Done.