Toradex Verdin iMX8M Plus

.. _verdin_imx8mp:

Toradex Verdin iMX8M Plus SoM
#############################

Overview
********

The Verdin iMX8M Plus is a Computer on Module (CoM) developed by Toradex. It is based on the NXP®
i.MX 8M Plus family of processors (or System on Chips - SoCs).

The Verdin iMX8M Plus family consists of:

+-------------------------------------------------+-----------------------+
| CoM                                             | SoC                   |
+=================================================+=======================+
| Verdin iMX8M Plus Quad 8GB Wi-Fi / Bluetooth IT | i.MX 8M Plus Quad     |
+-------------------------------------------------+-----------------------+
| Verdin iMX8M Plus Quad 4GB Wi-Fi / Bluetooth IT | i.MX 8M Plus Quad     |
+-------------------------------------------------+-----------------------+
| Verdin iMX8M Plus Quad 4GB IT                   | i.MX 8M Plus Quad     |
+-------------------------------------------------+-----------------------+
| Verdin iMX8M Plus Quad 2GB Wi-Fi / Bluetooth IT | i.MX 8M Plus Quad     |
+-------------------------------------------------+-----------------------+
| Verdin iMX8M Plus QuadLite 1GB IT               | i.MX 8M Plus QuadLite |
+-------------------------------------------------+-----------------------+

Quoting NXP:

   The i.MX 8M Plus family focuses on machine learning and vision, advanced multimedia, and
   industrial automation with high reliability. It is built to meet the needs of Smart Home,
   Building, City and Industry 4.0 applications.

The Verdin iMX8M Plus integrates a total of 4 Arm Cortex™-A53 CPUs, operating at 1.6 GHz, alongside
a single Arm Cortex™-M7F microcontroller operating at 800 MHz.

.. figure:: ../../../../../../../boards/toradex/verdin_imx8mp/doc/verdin_imx8mp_front.jpg
   :align: center
   :alt: Toradex Verdin iMX8M Plus

   Toradex Verdin iMX8M Plus (Credit: Toradex)

Regarding the Cortex-A53 cluster, it employs the ARMv8-A architecture as a mid-range and
energy-efficient processor. With four cores in this cluster, each core is equipped with its own L1
memory system. Moreover, the cluster incorporates a unified L2 cache that offers supplementary
functions. This cache is housed within a single APR region. Facilitating debugging processes, the
cores support both real-time trace through the ETM system and static debugging via JTAG.
Furthermore, the platform features support for real-time trace capabilities, achieved through ARM's
CoreSight ETM modules, and also enables cross-triggering by utilizing CTI and CTM modules.

The Arm® Cortex®-M7 microcontroller is indicated for Real-time control, combining high-performance
with a minimal interrupt latency. It stands out for its compatibility with existing Cortex-M profile
processors. The microcontroller employs an efficient in-order super-scalar pipeline, allowing
dual-issued instructions such as load/load and load/store pairs, thanks to its multiple memory
interfaces. These interfaces encompass Tightly-Coupled Memory (TCM), Harvard caches, and an AXI
master interface. The Arm Cortex-M7 Platform boasts features like a 32 KB L1 Instruction Cache, 32
KB L1 Data Cache, Floating Point Unit (FPU) with FPv5 architecture support, and an Internal Trace
(TRC) mechanism. Furthermore, the chip supports 160 IRQs, and integrates crucial Arm CoreSight
components including ETM and CTI, dedicated to facilitating debug and trace functions.

Hardware
********

- SoC name: NXP® i.MX 8M Plus
- CPU Type:	4x Arm Cortex™-A53 (1.6 GHz)
- Microcontroller:	1x Arm Cortex™-M7F (800 MHz)

- Memory:

  - RAM -> A53: 1GB, 2GB, 4GB or 8GB
  - RAM -> M7: 3x32KB (TCML, TCMU, OCRAM_S), 1x128KB (OCRAM) and 1x256MB (DDR)
  - Flash -> A53: Up to 32GB eMMC

- Connectivity:

  - USB 3.1: 1x Host / 1x OTG (Gen 1)
  - USB 2.0: 1x Host / 1x OTG
  - Ethernet Gigabit with TSN (+2nd RGMII)
  - Wi-Fi Dual-band 802.11ac 2x2 MU-MIMO
  - Bluetooth 5
  - 5x I2C
  - 3x SPI
  - 1 QSPI
  - 4x UART
  - Up to 92 GPIO
  - 4x Analog Input
  - 2x CAN (FlexCAN)

- Multimedia:

   - Neural Processing Unit (NPU)
   - Image Signal Processor (ISP)
   - 2D and 3D acceleration
   - HDMI, MIPI-DSI and MIPI-CSI interface

For more information about the Verdin iMX8M Plus and the i.MX 8M Plus SoC refer to these links:

- `i.MX 8M Plus Applications Processor page`_
- `Verdin iMX8M Plus homepage`_
- `Verdin iMX8M Plus developer page`_
- `Verdin Development Board developer page`_
- `Verdin iMX8M Plus Datasheet`_
- `Verdin Development Board Datasheet`_

Supported Features
==================

The Zephyr verdin_imx8mp_m7 board configuration supports the following hardware features:

+-----------+------------+-------------------------------------+
| Interface | Controller | Driver/Component                    |
+===========+============+=====================================+
| NVIC      | on-chip    | nested vector interrupt controller  |
+-----------+------------+-------------------------------------+
| SYSTICK   | on-chip    | systick                             |
+-----------+------------+-------------------------------------+
| CLOCK     | on-chip    | clock_control                       |
+-----------+------------+-------------------------------------+
| PINMUX    | on-chip    | pinmux                              |
+-----------+------------+-------------------------------------+
| UART      | on-chip    | serial port-polling;                |
|           |            | serial port-interrupt               |
+-----------+------------+-------------------------------------+
| GPIO      | on-chip    | GPIO output                         |
|           |            | GPIO input                          |
+-----------+------------+-------------------------------------+

The default configuration can be found in the defconfig file:

- :zephyr_file:`boards/toradex/verdin_imx8mp/verdin_imx8mp_mimx8ml8_m7_defconfig`, if you choose to use
  the ITCM memory.

- :zephyr_file:`boards/toradex/verdin_imx8mp/verdin_imx8mp_mimx8ml8_m7_ddr_defconfig`, if you choose to use
  the DDR memory.

It is recommended to disable peripherals used by the M7 core on the Linux host.

Other hardware features are not currently supported by the port.

Connections and IOs
===================

UART
----

Zephyr is configured to use the UART4 by default, which is connected to the FTDI USB converter on
most Toradex carrier boards.

This is also the UART connected to WiFi/BT chip in modules that have the WiFi/BT chip. Therefore, if
UART4 is used, WiFI/BT will not work properly.

If the WiFi/BT is needed, then another UART should be used for Zephyr (UART1 for example). You can
change the UART by changing the ``zephyr,console`` and ``zephyr,shell-uart`` in the
:zephyr_file:`boards/toradex/verdin_imx8mp/verdin_imx8mp_mimx8ml8_m7.dts` or
:zephyr_file:`boards/toradex/verdin_imx8mp/verdin_imx8mp_mimx8ml8_m7_ddr.dts` file.

+---------------+-----------------+---------------------------+
| Board Name    | SoC Name        | Usage                     |
+===============+=================+===========================+
| UART_1        | UART1           | General purpose UART      |
+---------------+-----------------+---------------------------+
| UART_4        | UART4           | Cortex-M4 debug UART      |
+---------------+-----------------+---------------------------+

GPIO
----

All the GPIO banks available are enabled in the :zephyr_file:`dts/arm/nxp/nxp_imx8ml_m7.dtsi`.

System Clock
============

The M7 Core is configured to run at a 800 MHz clock speed.

Serial Port
===========

The i.MX8M Plus SoC has four UARTs. UART_4 is configured for the console and the remaining are not
used/tested.

Programming and Debugging
*************************

The Verdin iMX8M Plus board doesn't have QSPI flash for the M7, and it needs to be started by the
A53 core. The A53 core is responsible to load the M7 binary application into the RAM, put the M7 in
reset, set the M7 Program Counter and Stack Pointer, and get the M7 out of reset. The A53 can
perform these steps at bootloader level or after the Linux system has booted.

The M7 can use up to 3 different RAMs (currently, only two configurations are supported: ITCM and
DDR). These are the memory mapping for A53 and M7:

+------------+-------------------------+------------------------+-----------------------+----------------------+
| Region     | Cortex-A53              | Cortex-M7 (System Bus) | Cortex-M7 (Code Bus)  | Size                 |
+============+=========================+========================+=======================+======================+
| OCRAM      | 0x00900000-0x0098FFFF   | 0x20200000-0x2028FFFF  | 0x00900000-0x0098FFFF | 576KB                |
+------------+-------------------------+------------------------+-----------------------+----------------------+
| DTCM       | 0x00800000-0x0081FFFF   | 0x20000000-0x2001FFFF  |                       | 128KB                |
+------------+-------------------------+------------------------+-----------------------+----------------------+
| ITCM       | 0x007E0000-0x007FFFFF   |                        | 0x00000000-0x0001FFFF | 128KB                |
+------------+-------------------------+------------------------+-----------------------+----------------------+
| OCRAM_S    | 0x00180000-0x00188FFF   | 0x20180000-0x20188FFF  | 0x00180000-0x00188FFF | 36KB                 |
+------------+-------------------------+------------------------+-----------------------+----------------------+
| DDR        | 0x80000000-0x803FFFFF   | 0x80200000-0x803FFFFF  | 0x80000000-0x801FFFFF | 2MB                  |
+------------+-------------------------+------------------------+-----------------------+----------------------+

For more information about memory mapping see the `i.MX 8M Plus Applications Processor Reference
Manual`_  (section 2.1 to 2.3)

At compilation time you have to choose which RAM will be used. To facilitate this process, there are
two targets available:

- ``verdin_imx8mp/mimx8ml8/m7``, which uses the ITCM configuration.
- ``verdin_imx8mp/mimx8ml8/m7/ddr``, which uses the DDR configuration.


Starting the Cortex-M7 via U-Boot
=================================

Load and run Zephyr on M7 from A53 using u-boot by copying the compiled ``zephyr.bin`` to the first
FAT partition of the SD card and plug the SD card into the board. Power it up and stop the u-boot
execution at prompt.

Load the M7 binary onto the desired memory and start its execution using:

ITCM
====

Loading the binary from an EXT4 partition:

.. code-block:: shell

   ext4load mmc 2:2 ${loadaddr} /<path-to-binary>/zephyr.bin
   cp.b ${loadaddr} 0x7e0000 <size_of_binary_in_bytes>
   bootaux 0x7e0000

DDR
===

Loading the binary from an EXT4 partition:

.. code-block:: shell

   ext4load mmc 2:2 ${loadaddr} /<path-to-binary>/zephyr.bin
   cp.b ${loadaddr} 0x80000000 <size_of_binary_in_bytes>
   bootaux 0x80000000

Debugging
=========

Toradex Verdin iMX8M Plus SoM can be debugged by connecting an external JLink JTAG debugger to the
X56 debug connector and to the PC, or simply connecting a USB-C to X66 on the Verdin Development
Board. Then, the application can be debugged using the usual way.

Here is an example for the :ref:`hello_world` application.

.. zephyr-app-commands::
   :zephyr-app: samples/hello_world
   :board: verdin_imx8mp/mimx8ml8/m7/ddr
   :goals: debug

Open a serial terminal, step through the application in your debugger, and you
should see the following message in the terminal:

.. code-block:: console

   *** Booting Zephyr OS build zephyr-v3.4.0-2300-g03905f7e55d2  ***
   Hello World! verdin_imx8mp

References
==========

- `How to Load Compiled Binaries into Cortex-M`_
- `Cortex-M JTAG Debugging`_
- `NXP website`_

.. _NXP website:
   https://www.nxp.com/design/development-boards/i-mx-evaluation-and-development-boards/evaluation-kit-for-the-i-mx-8m-plus-applications-processor:8MPLUSLPD4-EVK

.. _i.MX 8M Plus Applications Processor Reference Manual:
   https://www.nxp.com/webapp/Download?colCode=IMX8MPRM

.. _How to Load Compiled Binaries into Cortex-M:
   https://developer.toradex.com/software/real-time/cortex-m/how-to-load-binaries

.. _Cortex-M JTAG Debugging:
   https://developer.toradex.com/software/real-time/cortex-m/cortexm-jtag-debugging/

.. _i.MX 8M Plus Applications Processor page:
   https://www.nxp.com/products/processors-and-microcontrollers/arm-processors/i-mx-applications-processors/i-mx-8-applications-processors/i-mx-8m-plus-arm-cortex-a53-machine-learning-vision-multimedia-and-industrial-iot:IMX8MPLUS

.. _Verdin iMX8M Plus homepage:
   https://www.toradex.com/computer-on-modules/verdin-arm-family/nxp-imx-8m-plus

.. _Verdin iMX8M Plus developer page:
   https://developer.toradex.com/hardware/verdin-som-family/modules/verdin-imx8m-plus

.. _Verdin Development Board developer page:
   https://developer.toradex.com/hardware/verdin-som-family/carrier-boards/verdin-development-board/

.. _Verdin iMX8M Plus Datasheet:
   https://docs.toradex.com/110977-verdin_imx8m_plus_v1.1_datasheet.pdf

.. _Verdin Development Board Datasheet:
   https://docs.toradex.com/109463-verdin_development_board_datasheet_v1.1.pdf