.. _mps2_armv7m_board:

ARM V2M MPS2 Armv7-m (AN385/AN386/AN500)
########################################

Overview
********

The ``mps2/an385``, ``mps2/an386``, and ``mps2/an500`` board targets are three of
the mps2 Armv7-m based board targets supported in Zephyr. This document
provides details about the support provided for these three Armv7-m mps2 board targets
(**AN385**, **AN386**, **AN500**) and the following devices:

- Nested Vectored Interrupt Controller (NVIC)
- System Tick System Clock (SYSTICK)
- Cortex-M System Design Kit UART

.. image:: img/mps2.jpg
     :align: center
     :alt: ARM V2M MPS2

In addition to enabling actual hardware usage, these board targets can
also use `FVP`_ to emulate the platforms running on the MPS2+.

More information about the board can be found at the `V2M MPS2 Website`_.

The application note for each of the board can be found as follows:

- AN385 can be found at `Application Note AN385`_
- AN386 can be found at `Application Note AN386`_
- AN500 can be found at `Application Note AN500`_

AN385 is also supported to run with QEMU, and is set to run with QEMU by default.

.. note::
   These board targets makes no claims about its suitability for use
   with actual MPS2 hardware systems, or any other hardware
   system.

Hardware
********

ARM V2M MPS2 provides the following hardware components:

- ARM Cortex-M Chip
- ARM IoT Subsystem for Cortex-M
- Form factor: 140x120cm
- ZBTSRAM: 8MB single cycle SRAM, 16MB PSRAM
- Video: QSVGA touch screen panel, 4bit RGB VGA connector
- Audio: Audio Codec
- Debug:

  - ARM JTAG20 connector
  - ARM parallel trace connector (MICTOR38)
  - 20 pin Cortex debug connector
  - 10 pin Cortex debug connector
  - ILA connector for FPGA debug

- Expansion

  - GPIO
  - SPI

.. note::
   4 MB of flash memory (in ZBTSRAM 1, starting at address 0x00400000) and 4 MB of RAM
   (in ZBTSRAM 2 & 3, starting at address 0x20000000) are available.

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

The ``mps2/an385``, ``mps2/an386``, and ``mps2/an500`` board targets support the following hardware features:

+-----------+------------+-------------------------------------+
| Interface | Controller | Driver/Component                    |
+===========+============+=====================================+
| NVIC      | on-chip    | nested vector interrupt controller  |
+-----------+------------+-------------------------------------+
| SYSTICK   | on-chip    | systick                             |
+-----------+------------+-------------------------------------+
| UART      | on-chip    | serial port-polling;                |
|           |            | serial port-interrupt               |
+-----------+------------+-------------------------------------+
| GPIO      | on-chip    | gpio                                |
+-----------+------------+-------------------------------------+
| WATCHDOG  | on-chip    | watchdog                            |
+-----------+------------+-------------------------------------+
| TIMER     | on-chip    | counter                             |
+-----------+------------+-------------------------------------+
| DUALTIMER | on-chip    | counter                             |
+-----------+------------+-------------------------------------+

Other hardware features are not currently supported by the port.
See the `V2M MPS2 Website`_ for a complete list of V2M MPS2 board hardware
features.

The default configuration can be found in
:zephyr_file:`boards/arm/mps2/mps2_an385_defconfig`
or similarly in ``mps2_anxxx_defconfig`` for the other applicable boards.

Interrupt Controller
====================

MPS2 is a Cortex-M based SoC and has 15 fixed exceptions and 45 IRQs.

A Cortex-M3/4/7-based board uses vectored exceptions. This means each exception
calls a handler directly from the vector table.

Handlers are provided for exceptions 1-6, 11-12, and 14-15. The table here
identifies the handlers used for each exception.

+------+------------+----------------+--------------------------+
| Exc# | Name       | Remarks        | Used by Zephyr Kernel    |
+======+============+================+==========================+
| 1    | Reset      |                | system initialization    |
+------+------------+----------------+--------------------------+
| 2    | NMI        |                | system fatal error       |
+------+------------+----------------+--------------------------+
| 3    | Hard fault |                | system fatal error       |
+------+------------+----------------+--------------------------+
| 4    | MemManage  | MPU fault      | system fatal error       |
+------+------------+----------------+--------------------------+
| 5    | Bus        |                | system fatal error       |
+------+------------+----------------+--------------------------+
| 6    | Usage      | undefined      | system fatal error       |
|      | fault      | instruction,   |                          |
|      |            | or switch      |                          |
|      |            | attempt to ARM |                          |
|      |            | mode           |                          |
+------+------------+----------------+--------------------------+
| 11   | SVC        |                | system calls, kernel     |
|      |            |                | run-time exceptions,     |
|      |            |                | and IRQ offloading       |
+------+------------+----------------+--------------------------+
| 12   | Debug      |                | system fatal error       |
|      | monitor    |                |                          |
+------+------------+----------------+--------------------------+
| 14   | PendSV     |                | context switch           |
+------+------------+----------------+--------------------------+
| 15   | SYSTICK    |                | system clock             |
+------+------------+----------------+--------------------------+

Pin Mapping
===========

The ARM V2M MPS2 Board has 4 GPIO controllers. These controllers are responsible
for pin muxing, input/output, pull-up, etc.

All GPIO controller pins are exposed via the following sequence of pin numbers:

- Pins 0 - 15 are for GPIO 0
- Pins 16 - 31 are for GPIO 1
- Pins 32 -  47 are for GPIO 2
- Pins 48 -  51 are for GPIO 3

Mapping from the ARM MPS2 Board pins to GPIO controllers:

.. rst-class:: rst-columns

   - D0 : EXT_0
   - D1 : EXT_4
   - D2 : EXT_2
   - D3 : EXT_3
   - D4 : EXT_1
   - D5 : EXT_6
   - D6 : EXT_7
   - D7 : EXT_8
   - D8 : EXT_9
   - D9 : EXT_10
   - D10 : EXT_12
   - D11 : EXT_13
   - D12 : EXT_14
   - D13 : EXT_11
   - D14 : EXT_15
   - D15 : EXT_5
   - D16 : EXT_16
   - D17 : EXT_17
   - D18 : EXT_18
   - D19 : EXT_19
   - D20 : EXT_20
   - D21 : EXT_21
   - D22 : EXT_22
   - D23 : EXT_23
   - D24 : EXT_24
   - D25 : EXT_25
   - D26 : EXT_26
   - D27 : EXT_30
   - D28 : EXT_28
   - D29 : EXT_29
   - D30 : EXT_27
   - D31 : EXT_32
   - D32 : EXT_33
   - D33 : EXT_34
   - D34 : EXT_35
   - D35 : EXT_36
   - D36 : EXT_38
   - D37 : EXT_39
   - D38 : EXT_40
   - D39 : EXT_44
   - D40 : EXT_41
   - D41 : EXT_31
   - D42 : EXT_37
   - D43 : EXT_42
   - D44 : EXT_43
   - D45 : EXT_45
   - D46 : EXT_46
   - D47 : EXT_47
   - D48 : EXT_48
   - D49 : EXT_49
   - D50 : EXT_50
   - D51 : EXT_51

Peripheral Mapping:

.. rst-class:: rst-columns

   - UART_3_RX : D0
   - UART_3_TX : D1
   - SPI_3_CS : D10
   - SPI_3_MOSI : D11
   - SPI_3_MISO : D12
   - SPI_3_SCLK : D13
   - I2C_3_SDA : D14
   - I2C_3_SCL : D15
   - UART_4_RX : D26
   - UART_4_TX : D30
   - SPI_4_CS : D36
   - SPI_4_MOSI : D37
   - SPI_4_MISO : D38
   - SPI_4_SCK : D39
   - I2C_4_SDA : D40
   - I2C_4_SCL : D41

For more details please refer to `MPS2 Technical Reference Manual (TRM)`_.

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

The V2M MPS2 main clock is 24 MHz.

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

The V2M MPS2 processor has five UARTs. Both the UARTs have only two wires for
RX/TX and no flow control (CTS/RTS) or FIFO. The Zephyr console output, by
default, is utilizing UART0.

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

Flashing
========

V2M MPS2 provides:

- A USB connection to the host computer, which exposes a Mass Storage and an
  USB Serial Port.
- A Serial Flash device, which implements the USB flash disk file storage.
- A physical UART connection which is relayed over interface USB Serial port.

Flashing an application to V2M MPS2
-----------------------------------

Here is an example for the :zephyr:code-sample:`hello_world` application with AN385.

.. zephyr-app-commands::
   :zephyr-app: samples/hello_world
   :board: mps2/an385
   :goals: build

Connect the V2M MPS2 to your host computer using the USB port and you should
see a USB connection which exposes a Mass Storage and a USB Serial Port.
Copy the generated zephyr.bin in the exposed drive.
Reset the board and you should be able to see on the corresponding Serial Port
the following message:

.. code-block:: console

   Hello World! arm

Running an applicatoin with FVP
-------------------------------

Here is the same example for running with FVP.
Set the ``ARMFVP_BIN_PATH`` environemnt variable to the location of your FVP you have downloaded from `here <FVP_>`_

.. code-block:: console

    export ARMFVP_BIN_PATH=/home/../FVP_MPS2/

Then build with the same command you would use normally, and run with ``west build -t run_armfvp``.

.. _V2M MPS2 Website:
   https://developer.mbed.org/platforms/ARM-MPS2/

.. _MPS2 Technical Reference Manual (TRM):
   https://developer.arm.com/documentation/100112/0200/

.. _Application Note AN385:
   https://documentation-service.arm.com/static/5ed107a5ca06a95ce53f89e3

.. _Application Note AN386:
   https://documentation-service.arm.com/static/5ed1094dca06a95ce53f8a9f

.. _Application Note AN500:
   https://documentation-service.arm.com/static/5ed112fcca06a95ce53f8eb3

.. _FVP:
   https://developer.arm.com/downloads/view/FMFVP
