.. _v2m_beetle_board:
ARM V2M Beetle
##############
Overview
********
The v2m_beetle board configuration is used by Zephyr applications that run on
the V2M Beetle board. It provides support for the Beetle ARM Cortex-M3 CPU and
the following devices:
- Nested Vectored Interrupt Controller (NVIC)
- System Tick System Clock (SYSTICK)
- Cortex-M System Design Kit GPIO
- Cortex-M System Design Kit UART
.. image:: ../../../../../../../../../zephyr/boards/arm/v2m_beetle/doc/img/v2m_beetle.png
:width: 442px
:align: center
:height: 335px
:alt: ARM V2M Beetle
More information about the board can be found at the `V2M Beetle Website`_.
Hardware
********
ARM V2M BEETLE provides the following hardware components:
- ARM Cortex-M3
- ARM IoT Subsystem for Cortex-M
- CORDIO Bluetooth Smart radio
- Memory
- 256KB of embedded flash
- 128KB SRAM
- 2MB of external QSPI flash.
- Debug
- JTAG, SWD & 4 bit TRACE
- CMSIS-DAP with a virtual UART port
- Arduino interface
- GPIO, UART, SPI, I2C
- Analog signals
Supported Features
===================
The v2m_beetle 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 |
+-----------+------------+-------------------------------------+
| PINMUX | on-chip | pinmux |
+-----------+------------+-------------------------------------+
| GPIO | on-chip | gpio |
+-----------+------------+-------------------------------------+
| WATCHDOG | on-chip | watchdog |
+-----------+------------+-------------------------------------+
| TIMER | on-chip | timer |
+-----------+------------+-------------------------------------+
Other hardware features are not currently supported by the port.
See the `V2M Beetle Website`_ for a complete list of V2M Beetle board hardware
features.
The default configuration can be found in the defconfig file:
.. code-block:: console
boards/arm/v2m_beetle/v2m_beetle_defconfig
Interrupt Controller
====================
Beetle 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 Beetle 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
Mapping from the ARM V2M Beetle Board pins to GPIO controllers:
.. rst-class:: rst-columns
- D0 : P0_0
- D1 : P0_1
- D2 : P0_2
- D3 : P0_3
- D4 : P0_4
- D5 : P0_5
- D6 : P0_6
- D7 : P0_7
- D8 : P0_8
- D9 : P0_9
- D10 : P0_10
- D11 : P0_11
- D12 : P0_12
- D13 : P0_13
- D14 : P0_14
- D15 : P0_15
- D16 : P1_0
- D17 : P1_1
- D18 : P1_2
- D19 : P1_3
- D20 : P1_4
- D21 : P1_5
- D22 : P1_6
- D23 : P1_7
- D24 : P1_8
- D25 : P1_9
- D26 : P1_10
- D27 : P1_11
- D28 : P1_12
- D29 : P1_13
- D30 : P1_14
- D31 : P1_15
Peripheral Mapping:
.. rst-class:: rst-columns
- UART_0_RX : D0
- UART_0_TX : D1
- SPI_0_CS : D10
- SPI_0_MOSI : D11
- SPI_0_MISO : D12
- SPI_0_SCLK : D13
- I2C_0_SCL : D14
- I2C_0_SDA : D15
- UART_1_RX : D16
- UART_1_TX : D17
- SPI_1_CS : D18
- SPI_1_MOSI : D19
- SPI_1_MISO : D20
- SPI_1_SCK : D21
- I2C_1_SDA : D22
- I2C_1_SCL : D23
For mode details please refer to `Beetle Technical Reference Manual (TRM)`_.
System Clock
============
V2M Beetle has one external and two on-chip oscillators. The slow clock is
32.768 kHz, and the main clock is 24 MHz. The processor can set up PLL to drive
the master clock.
Serial Port
===========
The ARM Beetle processor has two 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 UART1.
Programming and Debugging
*************************
Flashing
========
CMSIS DAP
---------
V2M Beetle 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.
This interfaces are exposed via CMSIS DAP. For more details please refer
to `CMSIS-DAP Website`_.
Flashing an application to V2M Beetle
-------------------------------------
You can build applications in the usual way. Here is an example for
the :ref:`hello_world` application.
.. zephyr-app-commands::
:zephyr-app: samples/hello_world
:board: v2m_beetle
:goals: build
Connect the V2M Beetle to your host computer using the USB port and you should
see a USB connection which exposes a Mass Storage (MBED) and a USB Serial Port.
Copy the generated zephyr.bin in the MBED 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 Beetle Website:
https://www.arm.com/products/tools/development-boards/versatile-express/beetle_iot_evaluation_platform.php
.. _Beetle Technical Reference Manual (TRM):
https://developer.arm.com/-/media/developer/products/system-design-tools/versatile-express-family/V2M-Beetle_TRM_draft.pdf?la=en
.. _CMSIS-DAP Website:
https://github.com/mbedmicro/CMSIS-DAP