.. _sam4s_xplained:

SAM4S Xplained
################

Overview
********

The SAM4S Xplained evaluation kit is a development platform to evaluate the
Atmel SAM4S series microcontrollers.

.. image:: img/sam4s_xplained.png
     :width: 500px
     :align: center
     :alt: SAM4S Xplained

Hardware
********

- ATSAM4S16C ARM Cortex-M4 Processor
- 12 MHz crystal oscillator
- internal 32.768 kHz crystal oscillator
- IS66WV51216DALL 8 Mb SRAM
- Micro-AB USB device
- Micro-AB USB debug interface supporting SEGGER OB and Virtual COM Port and
  Data
- One reset and one user pushbutton
- 2 yellow user LEDs
- IC pads for external flash chip

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

The sam4s_xplained 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                         |
+-----------+------------+-------------------------------------+

Other hardware features are not currently supported by Zephyr.

The default configuration can be found in the Kconfig
:file:`boards/arm/sam4s_xplained/sam4s_xplained_defconfig`.

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

The `SAM4S Xplained Online User Guide`_ has detailed information about board
connections. Download the `SAM4S Xplained Schematic`_ for more detail.

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

The SAM4S MCU is configured to use the 12 MHz internal oscillator on the board
with the on-chip PLL to generate an 84 MHz system clock.

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

The ATSAM4S16C MCU has 2 UARTs and 2 USARTs. One of the UARTs (UART0) is
connected to the Segger J-Link OB chip (the AT91SAM3U4 is programmed to be
Segger J-Link OB). Segger J-Link OB brings the UART out as a virtual COM port.

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

The SAM4S Xplained board comes with Segger `J-Link OB <https://www.segger.com/jlink-ob.html>`_. This provides a debug
interface to the SAM4S16C chip. You can use Ozone or JLink to communicate with
the SAM4S16C.

Flashing
========

#. Build the Zephyr kernel and the :ref:`hello_world` sample application:

   .. code-block:: console

      $ cd $ZEPHYR_BASE/samples/hello_world/
      $ make BOARD=sam4s_xplained

#. Connect the SAM4S Xplained board to your host computer using the USB debug
   port.

#. Run your favorite terminal program to listen for output. Under Linux the
   terminal should be :code:`/dev/ttyACM0`. For example:

   .. code-block:: console

      $ minicom -D /dev/ttyACM0 -o

   The -o option tells minicom not to send the modem initialization
   string. Connection should be configured as follows:

   - Speed: 115200
   - Data: 8 bits
   - Parity: None
   - Stop bits: 1

#. Download JLink from the Segger `JLink Downloads Page`_. Go to the section
   "J-Link Software and Documentation Pack" and install the "J-Link Software and
   Documentation pack for Linux".

#. To flash an image open JLink and enter the following:

   .. code-block:: console

      JLink> device at91sam4s16c
      // Hit enter to accept JTAG as the default and the other default JTAG settings
      JLink> connect
      .
      .
      .
      Device "ATSAM4S16C" selected.


      TotalIRLen = 4, IRPrint = 0x01
      AP-IDR: 0x24770011, Type: AHB-AP
      Found Cortex-M4 r0p1, Little endian.
      FPUnit: 6 code (BP) slots and 2 literal slots
      CoreSight components:
      ROMTbl 0 @ E00FF000
      ROMTbl 0 [0]: FFF0F000, CID: B105E00D, PID: 000BB000 SCS
      ROMTbl 0 [1]: FFF02000, CID: B105E00D, PID: 003BB002 DWT
      ROMTbl 0 [2]: FFF03000, CID: B105E00D, PID: 002BB003 FPB
      ROMTbl 0 [3]: FFF01000, CID: B105E00D, PID: 003BB001 ITM
      ROMTbl 0 [4]: FFF41000, CID: B105900D, PID: 000BB9A1 TPIU
      Found 1 JTAG device, Total IRLen = 4:
      #0 Id: 0x4BA00477, IRLen: 04, IRPrint: 0x1, CoreSight JTAG-DP (ARM)
      Cortex-M4 identified.

      JLink> loadbin <zephyr.bin>, 0x400000
      Downloading file [/home/justin/Zephyr/zephyr/samples/hello_world/outdir/zephyr.bin]...
      Comparing flash   [100%] Done.
      Erasing flash     [100%] Done.
      Programming flash [100%] Done.
      Verifying flash   [100%] Done.
      J-Link: Flash download: Flash programming performed for 2 ranges (21504 bytes)
      J-Link: Flash download: Total time needed: 0.549s (Prepare: 0.200s, Compare: 0.150s, Erase: 0.020s, Program: 0.094s, Verify: 0.001s, Restore: 0.081s)
      O.K.
      JLink> r
      JLink> go

   You should see "Hello World! arm" in your terminal.


References
**********

.. target-notes::

.. _SAM4S Xplained Online User Guide:
    http://www.atmel.com/webdoc/sam4s16xplained/index.html

.. _JLink Downloads Page:
    https://www.segger.com/downloads/jlink

.. _SAM4S Xplained Schematic:
    http://www.atmel.com/tools/sam4s-xpld.aspx?tab=documents