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Arm-2D GPU

docs/src/integration/chip_vendors/arm/arm2d.rst

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.. _arm2d:

========== Arm-2D GPU

Arm-2D is not a GPU but an abstraction layer for 2D GPUs dedicated to Microcontrollers. It supports all Cortex-M processors ranging from Cortex-M0 to the latest Cortex-M85.

Arm-2D accelerates LVGL9 with two modes: Synchronous Mode and Asynchronous Mode.

  • When Helium and ACI (Arm Custom Instruction) are available, it is recommend to use Synchronous Mode to accelerate LVGL.
  • When Arm-2D backed 2D-GPUs are available, for example, DMAC-350 based 2D GPUs, it is recommend to use Asynchronous Mode to accelerate LVGL.

Arm-2D is an open-source project on GitHub. For more, please refer to: https://github.com/ARM-software/Arm-2D.

How to Use

In general:

  • you can set the macro :c:macro:LV_USE_DRAW_ARM2D_SYNC to 1 and :c:macro:LV_DRAW_SW_ASM to :c:macro:LV_DRAW_SW_ASM_HELIUM in lv_conf.h to enable Arm-2D synchronous acceleration for LVGL.
  • You can set the macro :c:macro:LV_USE_DRAW_ARM2D_ASYNC to 1 in lv_conf.h to enable Arm-2D Asynchronous acceleration for LVGL.

If you are using CMSIS-Pack <https://github.com/lvgl/lvgl/tree/master/env_support/cmsis-pack>__ to deploy the LVGL. You don't have to define the macro :c:macro:LV_USE_DRAW_ARM2D_SYNC manually, instead the lv_conf_cmsis.h will check the environment and set the :c:macro:LV_USE_DRAW_ARM2D_SYNC accordingly.

Design Considerations

As mentioned before, Arm-2D is an abstraction layer for 2D GPU; hence if there is no accelerator or dedicated instruction set (such as Helium or ACI) available for Arm-2D, it provides negligible performance boost for LVGL (sometimes worse) for regular Cortex-M processors.

We highly recommend you enable Arm-2D acceleration for LVGL when:

  • The target processors are Cortex-M55, Cortex-M52 and Cortex-M85
  • The target processors support Helium <https://developer.arm.com/documentation/102102/0103/?lang=en>__.
  • The device vendor provides an arm-2d compliant driver for their proprietary 2D accelerators and/or ACI (Arm Customized Instruction).
  • The target device contains DMAC-350 <https://community.arm.com/arm-community-blogs/b/internet-of-things-blog/posts/arm-corelink-dma-350-next-generation-direct-memory-access-for-endpoint-ai>__

Examples

  • A Cortex-M55 (supports Helium) based MDK Project, PC emulation is available. <https://github.com/lvgl/lv_port_an547_cm55_sim>__

API

.. API equals: lv_draw_sw_image_recolor_rgb888

.. API equals: lv_rgb888_blend_normal_to_rgb565_arm2d