.. _mps2_an385_board:

ARM V2M MPS2
############

Overview
********

The mps2/an385 board configuration is used by Zephyr applications that run on
the V2M MPS2 board. It provides support for the ARM Cortex-M3 (AN385) CPU and
the following devices:

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

.. image:: img/mps2_an385.jpg
     :align: center
     :alt: ARM V2M MPS2

In addition to enabling actual hardware usage, this board configuration can
also use QEMU to emulate the AN385 platform running on the MPS2+.

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

The Application Note AN385 can be found at `Application Note AN385`_.

.. note::
   This board configuration makes no claims about its suitability for use
   with actual MPS2 hardware systems using AN385, or any other hardware
   system. It has been tested on actual hardware, but its primary purpose is
   for use with QEMU and unit tests.

Hardware
********

ARM V2M MPS2 provides the following hardware components:

- ARM Cortex-M3 (AN385)
- 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 board configuration supports 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`

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

MPS2 is a Cortex-M3 based SoC and has 15 fixed exceptions and 45 IRQs.

A Cortex-M3/4-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 :ref:`hello_world` application.

.. 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


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

.. _MPS2 Technical Reference Manual (TRM):
   http://infocenter.arm.com/help/topic/com.arm.doc.100112_0200_05_en/versatile_express_cortex_m_prototyping_systems_v2m_mps2_and_v2m_mps2plus_technical_reference_100112_0200_05_en.pdf

.. _Application Note AN385:
   http://infocenter.arm.com/help/topic/com.arm.doc.dai0385c/DAI0385C_cortex_m3_on_v2m_mps2.pdf