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README ^^^^^^

This README discusses issues unique to NuttX configurations for the Atmel SAM4L Xplained Pro development board. This board features the ATSAM4LC4C MCU.

The SAM4L Xplained Pro Starter Kit is bundled with four modules:

  1. I/O1 - An MMC/SD card slot, PWM LED control, ADC light sensor, UART loopback, TWI AT30TSE758 Temperature sensor.
  2. OLED1 - An OLED plus 3 additional switches and 3 additional LEDs
  3. SLCD1 - A segment LCD that connects directly to the "EXT5 SEGMENT LCD" connector
  4. PROTO1 - A prototyping board with logic on board (other than power-related logic).

Contents ^^^^^^^^

  • Modules
  • LEDs
  • Serial Consoles
  • SAM4L Xplained Pro-specific Configuration Options
  • Configurations

Modules ^^^^^^^ The SAM4L Xplained Pro Starter Kit is bundled with four modules:

I/O1

The primary function of this module is to provide SD card support, but the full list of modules features include:

- microSD card connector (SPI interface)
- PWM (LED control)
- ADC (light sensor)
- UART loopback
- TWI AT30TSE758 Temperature sensor with EEPROM

SPI is available on two of the SAM4L Xplained connectors, EXT1 and EXT2.
They mate with the I/O1 connector as indicated in this table.

I/O1 Connector
--------------
I/O1              EXT1                 EXT2                 Other use of either pin
----------------- -------------------- -------------------- ------------------------------------
1  ID             1                    1
2  GND            2       GND          2
3  LIGHT_SENSOR   3  PA04 ADCIFE/AD0   3  PA07 ADCIFE/AD2
4  LP_OUT         4  PA05 ADCIFE/AD1   4  PB02 ADCIFE/AD3
5  GPIO1          5  PB12 GPIO         5  PC08 GPIO         PB12 and PC8 on EXT5
6  GPIO2          6  PC02 GPIO         6  PB10 GPIO         PB10 on EXT5
7  LED            7  PC00 TC/1/A0      7  PC04 TC/1/A2
8  LP_IN          8  PC01 TC/1/B0      8  PC05 TC/1/B2      PC05 on EXT5
9  TEMP_ALERT     9  PC25 EIC/EXTINT2  9  PC06 EIC/EXTINT8  PC25 on EXT5
10 microSD_DETECT 10 PB13 SPI/NPCS1    10 PC09 GPIO         PB13 on EXT5
11 TWI SDA        11 PA23 TWIMS/0/TWD  11 PB14 TWIMS/3/TWD  PB14 on EXT3&4, PA23 and PB14 on EXT5
12 TWI SCL        12 PA24 TWIMS/0/TWCK 12 PB15 TWIMS/3/TWCK PB15 on EXT3&4, PA24 and PB15 on EXT5
13 UART RX        13 PB00 USART/0/RXD  13 PC26 USART/1/RXD  PB00 on EXT4, PC26 on EXT3&5
14 UART TX        14 PB01 USART/0/TXD  14 PC27 USART/1/TXD  PB01 on EXT4, PC27 on EXT3&5
15 microSD_SS     15 PC03 SPI/NPCS0    15 PB11 SPI/NPCS2    PB11 on EXT5
16 SPI_MOSI       16 PA22 SPI/MOSI     16 PA22 SPI/MOSI     PA22 on EXT5
17 SPI_MISO       17 PA21 SPI/MISO     17 PA21 SPI/MISO     PA21 on EXT5
18 SPI_SCK        18 PC30 SPI/SCK      18 PC30 SPI/SCK      PC30 on EXT5
19 GND            19      GND             GND
20 VCC            20      VCC             VCC

The mapping between the I/O1 pins and the SD connector are shown in the
following table.

SD Card Connection
------------------
I/O1 SD   PIN Description
---- ---- --- -------------------------------------------------
     D2   1   Data line 2 (not used)
15   D3   2   Data line 3. Active low chip select, pulled high
16   CMD  3   Command line, connected to SPI_MOSI.
20   VDD  4
18   CLK  5   Clock line, connected to SPI_SCK.
2/19 GND  6
17   D0   7   Data line 0, connected to SPI_MISO.
     D1   8   Data line 1 (not used)
10   SW_A 9   Card detect
2/19 SW_B 10  GND

Card Detect
-----------
When a microSD card is put into the connector SW_A and SW_B are short-
circuited. SW_A is connected to the microSD_DETECT signal. To use this
as a card indicator remember to enable internal pullup in the target
device.

GPIOs
-----
So all that is required to connect the SD is configure the SPI

PIN EXT1           EXT2            Description
--- -------------- --------------- -------------------------------------
15  PC03 SPI/NPCS0 PB11 SPI/NPCS2  Active low chip select OUTPUT, pulled
                                   high on board.
10  PB13 SPI/NPCS1 10 PC09 GPIO    Active low card detect INPUT, must
                                   use internal pull-up.

Configuration Options:
----------------------
  CONFIG_SAM4L_XPLAINED_IOMODULE=y      : Informs the system that the
                                          I/O1 module is installed
  CONFIG_SAM4L_XPLAINED_IOMODULE_EXT1=y : The module is installed in EXT1
  CONFIG_SAM4L_XPLAINED_IOMODULE_EXT2=y : The mdoule is installed in EXT2

See the set-up in the discussion of the nsh configuration below for other
required configuration options.

NOTE: As of this writing, only the SD card slot is supported in the I/O1
module.

OLED1

This module provides an OLED plus 3 additional switches and 3 additional LEDs.

OLED1 Connector
--------------
OLED1             EXT1                 EXT2                 Other use of either pin
----------------- -------------------- -------------------- ------------------------------------
1  ID             1                    1
2  GND            2       GND          2
3  BUTTON2        3  PA04 ADCIFE/AD0   3  PA07 ADCIFE/AD2
4  BUTTON3        4  PA05 ADCIFE/AD1   4  PB02 ADCIFE/AD3
5  DATA_CMD_SEL   5  PB12 GPIO         5  PC08 GPIO         PB12 and PC8 on EXT5
6  LED3           6  PC02 GPIO         6  PB10 GPIO         PB10 on EXT5
7  LED1           7  PC00 TC/1/A0      7  PC04 TC/1/A2
8  LED2           8  PC01 TC/1/B0      8  PC05 TC/1/B2      PC05 on EXT5
9  BUTTON1        9  PC25 EIC/EXTINT2  9  PC06 EIC/EXTINT8  PC25 on EXT5
10 DISPLAY_RESET  10 PB13 SPI/NPCS1    10 PC09 GPIO         PB13 on EXT5
11 N/C            11 PA23 TWIMS/0/TWD  11 PB14 TWIMS/3/TWD  PB14 on EXT3&4, PA23 and PB14 on EXT5
12 N/C            12 PA24 TWIMS/0/TWCK 12 PB15 TWIMS/3/TWCK PB15 on EXT3&4, PA24 and PB15 on EXT5
13 N/C            13 PB00 USART/0/RXD  13 PC26 USART/1/RXD  PB00 on EXT4, PC26 on EXT3&5
14 N/C            14 PB01 USART/0/TXD  14 PC27 USART/1/TXD  PB01 on EXT4, PC27 on EXT3&5
15 DISPLAY_SS     15 PC03 SPI/NPCS0    15 PB11 SPI/NPCS2    PB11 on EXT5
16 SPI_MOSI       16 PA22 SPI/MOSI     16 PA22 SPI/MOSI     PA22 on EXT5
17 N/C            17 PA21 SPI/MISO     17 PA21 SPI/MISO     PA21 on EXT5
18 SPI_SCK        18 PC30 SPI/SCK      18 PC30 SPI/SCK      PC30 on EXT5
19 GND            19      GND             GND
20 VCC            20      VCC             VCC

Configuration Options:
----------------------
  CONFIG_SAM4L_XPLAINED_OLED1MODULE=y      : Informs the system that the
                                             I/O1 module is installed
  CONFIG_SAM4L_XPLAINED_OLED1MODULE_EXT1=y : The module is installed in EXT1
  CONFIG_SAM4L_XPLAINED_OLED1MODULE_EXT2=y : The mdoule is installed in EXT2

See the set-up in the discussion of the nsh configuration below for other
required configuration options.

SLCD1

This module provides a A segment LCD that connects directly to the "EXT5 SEGMENT LCD" connector

Configuration Options:
----------------------
  CONFIG_SAM4L_XPLAINED_SLCD1MODULE=y   : Informs the system that the
                                          I/O1 module is installed

See the set-up in the discussion of the nsh configuration below for other
required configuration options.

PROTO1

A prototyping board with logic on board (other than power-related logic). There is no built-in support for the PROTO1 module.

LEDs ^^^^ There are three LEDs on board the SAM4L Xplained Pro board: The EDBG controls two of the LEDs, a power LED and a status LED. There is only one user controllable LED, a yellow LED labeled LED0 near the SAM4L USB connector.

This LED is controlled by PC07 and LED0 can be activated by driving the PC07 to GND.

When CONFIG_ARCH_LEDS is defined in the NuttX configuration, NuttX will control LED0 as follows:

SYMBOL              Meaning                 LED0
------------------- ----------------------- ------
LED_STARTED         NuttX has been started  OFF
LED_HEAPALLOCATE    Heap has been allocated OFF
LED_IRQSENABLED     Interrupts enabled      OFF
LED_STACKCREATED    Idle stack created      ON
LED_INIRQ           In an interrupt         N/C
LED_SIGNAL          In a signal handler     N/C
LED_ASSERTION       An assertion failed     N/C
LED_PANIC           The system has crashed  FLASH

Thus is LED0 is statically on, NuttX has successfully booted and is, apparently, running normmally. If LED0 is flashing at approximately 2Hz, then a fatal error has been detected and the system has halted.

Serial Consoles ^^^^^^^^^^^^^^^

USART0 ------

USART0 is available on connectors EXT1 and EXT4

EXT1  EXT4  GPIO  Function
----  ---- ------ -----------
 13    13   PB00  USART0_RXD
 14    14   PB01  USART0_TXD
 19    19         GND
 20    20         VCC

If you have a TTL to RS-232 converter then this is the most convenient serial console to use. It is the default in all of these configurations. An option is to use the virtual COM port.

Virtual COM Port ----------------

The SAM4L Xplained Pro contains an Embedded Debugger (EDBG) that can be used to program and debug the ATSAM4LC4C using Serial Wire Debug (SWD). The Embedded debugger also include a Virtual Com port interface over USART1. Virtual COM port connections:

PC26 USART1 RXD
PC27 USART1 TXD

SAM4L Xplained Pro-specific Configuration Options ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

CONFIG_ARCH - Identifies the arch/ subdirectory.  This should
   be set to:

   CONFIG_ARCH=arm

CONFIG_ARCH_family - For use in C code:

   CONFIG_ARCH_ARM=y

CONFIG_ARCH_architecture - For use in C code:

   CONFIG_ARCH_CORTEXM4=y

CONFIG_ARCH_CHIP - Identifies the arch/*/chip subdirectory

   CONFIG_ARCH_CHIP="sam34"

CONFIG_ARCH_CHIP_name - For use in C code to identify the exact
   chip:

   CONFIG_ARCH_CHIP_SAM34
   CONFIG_ARCH_CHIP_SAM4L
   CONFIG_ARCH_CHIP_ATSAM4LC4C

CONFIG_ARCH_BOARD - Identifies the boards/ subdirectory and
   hence, the board that supports the particular chip or SoC.

   CONFIG_ARCH_BOARD=sam4l-xplained (for the SAM4L Xplained Pro development board)

CONFIG_ARCH_BOARD_name - For use in C code

   CONFIG_ARCH_BOARD_SAM4L_XPLAINED=y

CONFIG_ARCH_LOOPSPERMSEC - Must be calibrated for correct operation
   of delay loops

CONFIG_ENDIAN_BIG - define if big endian (default is little
   endian)

CONFIG_RAM_SIZE - Describes the installed DRAM (SRAM in this case):

   CONFIG_RAM_SIZE=0x00008000 (32Kb)

CONFIG_RAM_START - The start address of installed DRAM

   CONFIG_RAM_START=0x20000000

CONFIG_ARCH_LEDS - Use LEDs to show state. Unique to boards that
   have LEDs

CONFIG_ARCH_INTERRUPTSTACK - This architecture supports an interrupt
   stack. If defined, this symbol is the size of the interrupt
    stack in bytes.  If not defined, the user task stacks will be
  used during interrupt handling.

CONFIG_ARCH_STACKDUMP - Do stack dumps after assertions

CONFIG_ARCH_LEDS -  Use LEDs to show state. Unique to board architecture.

Individual subsystems can be enabled:

CPU
---
CONFIG_SAM34_OCD

HSB
---
CONFIG_SAM34_APBA
CONFIG_SAM34_AESA

PBA
---
CONFIG_SAM34_IISC
CONFIG_SAM34_SPI0
CONFIG_SAM34_TC0
CONFIG_SAM34_TC1
CONFIG_SAM34_TWIM0
CONFIG_SAM34_TWIS0
CONFIG_SAM34_TWIM1
CONFIG_SAM34_TWIS1
CONFIG_SAM34_USART0
CONFIG_SAM34_USART1
CONFIG_SAM34_USART2
CONFIG_SAM34_USART3
CONFIG_SAM34_ADC12B
CONFIG_SAM34_DACC
CONFIG_SAM34_ACC
CONFIG_SAM34_GLOC
CONFIG_SAM34_ABDACB
CONFIG_SAM34_TRNG
CONFIG_SAM34_PARC
CONFIG_SAM34_CATB
CONFIG_SAM34_TWIM2
CONFIG_SAM34_TWIM3
CONFIG_SAM34_LCDCA

PBB
---
CONFIG_SAM34_HRAMC1
CONFIG_SAM34_HMATRIX
CONFIG_SAM34_PDCA
CONFIG_SAM34_CRCCU
CONFIG_SAM34_USBC
CONFIG_SAM34_PEVC

PBC
---
CONFIG_SAM34_CHIPID
CONFIG_SAM34_FREQM

PBD
---
CONFIG_SAM34_AST
CONFIG_SAM34_WDT
CONFIG_SAM34_EIC
CONFIG_SAM34_PICOUART

Some subsystems can be configured to operate in different ways. The drivers need to know how to configure the subsystem.

CONFIG_SAM34_GPIOA_IRQ
CONFIG_SAM34_GPIOB_IRQ
CONFIG_SAM34_GPIOC_IRQ
CONFIG_USART0_SERIALDRIVER
CONFIG_USART1_SERIALDRIVER
CONFIG_USART2_SERIALDRIVER
CONFIG_USART3_SERIALDRIVER

ST91SAM4L specific device driver settings

CONFIG_U[S]ARTn_SERIAL_CONSOLE - selects the USARTn (n=0,1,2,3) or UART
       m (m=4,5) for the console and ttys0 (default is the USART1).
CONFIG_U[S]ARTn_RXBUFSIZE - Characters are buffered as received.
   This specific the size of the receive buffer
CONFIG_U[S]ARTn_TXBUFSIZE - Characters are buffered before
   being sent.  This specific the size of the transmit buffer
CONFIG_U[S]ARTn_BAUD - The configure BAUD of the UART.  Must be
CONFIG_U[S]ARTn_BITS - The number of bits.  Must be either 7 or 8.
CONFIG_U[S]ARTn_PARTIY - 0=no parity, 1=odd parity, 2=even parity
CONFIG_U[S]ARTn_2STOP - Two stop bits

Configurations ^^^^^^^^^^^^^^

Each SAM4L Xplained Pro configuration is maintained in a sub-directory and can be selected as follow:

tools/configure.sh sam4l-xplained:<subdir>

Before building, make sure the PATH environment variable includes the correct path to the directory than holds your toolchain binaries.

And then build NuttX by simply typing the following. At the conclusion of the make, the nuttx binary will reside in an ELF file called, simply, nuttx.

make

The <subdir> that is provided above as an argument to the tools/configure.sh must be is one of the following.

NOTE: These configurations use the mconf-based configuration tool. To change any of these configurations using that tool, you should:

a. Build and install the kconfig-mconf tool.  See nuttx/README.txt
   see additional README.txt files in the NuttX tools repository.

b. Execute 'make menuconfig' in nuttx/ in order to start the
   reconfiguration process.

NOTES:

  1. These configurations use the mconf-based configuration tool. To change any of these configurations using that tool, you should:
<!-- -->
a. Build and install the kconfig-mconf tool.  See nuttx/README.txt
   see additional README.txt files in the NuttX tools repository.

b. Execute 'make menuconfig' in nuttx/ in order to start the
   reconfiguration process.
  1. Unless stated otherwise, all configurations generate console output of on USART0 which is available on EXT1 or EXT4 (see the section "Serial Consoles" above). The virtual COM port could be used, instead, by reconfiguring to use USART1 instead of USART0:

    System Type -> AT91SAM3/4 Peripheral Support CONFIG_SAM_USART0=y CONFIG_SAM_USART1=n

    Device Drivers -> Serial Driver Support -> Serial Console CONFIG_USART0_SERIAL_CONSOLE=y

    Device Drivers -> Serial Driver Support -> USART0 Configuration CONFIG_USART0_2STOP=0 CONFIG_USART0_BAUD=115200 CONFIG_USART0_BITS=8 CONFIG_USART0_PARITY=0 CONFIG_USART0_RXBUFSIZE=256 CONFIG_USART0_TXBUFSIZE=256

  2. Unless otherwise stated, the configurations are setup for Linux (or any other POSIX environment like Cygwin under Windows):

    Build Setup: CONFIG_HOST_LINUX=y : Linux or other POSIX environment

  3. These configurations use the older, OABI, buildroot toolchain. But that is easily reconfigured:

    System Type -> Toolchain: CONFIG_ARM_TOOLCHAIN_BUILDROOT=y : Buildroot toolchain CONFIG_ARM_TOOLCHAIN_BUILDROOT_OABI=y : Older, OABI toolchain

    If you want to use the Atmel GCC toolchain, here are the steps to do so:

    Build Setup: CONFIG_HOST_WINDOWS=y : Windows CONFIG_HOST_CYGWIN=y : Using Cygwin or other POSIX environment

    System Type -> Toolchain: CONFIG_ARM_TOOLCHAIN_GNU_EABI=y : General GCC EABI toolchain under windows

    This re-configuration should be done before making NuttX or else the subsequent 'make' will fail. If you have already attempted building NuttX then you will have to 1) 'make distclean' to remove the old configuration, 2) 'tools/configure.sh sam3u-ek/ksnh' to start with a fresh configuration, and 3) perform the configuration changes above.

    Also, make sure that your PATH variable has the new path to your Atmel tools. Try 'which arm-none-eabi-gcc' to make sure that you are selecting the right tool.

    See also the "NOTE about Windows native toolchains" in the section call "GNU Toolchain Options" above.

Configuration sub-directories

nsh: This configuration directory will built the NuttShell. See NOTES above and below:

NOTES:

1. NOTE: If you get a compilation error like:

     libxx_new.cxx:74:40: error: 'operator new' takes type 'size_t'
                          ('unsigned int') as first parameter [-fper

   Sometimes NuttX and your toolchain will disagree on the underlying
   type of size_t; sometimes it is an 'unsigned int' and sometimes it is
   an 'unsigned long int'.  If this error occurs, then you may need to
   toggle the value of CONFIG_ARCH_SIZET_LONG.

2. If the I/O1 module is connected to the SAM4L Xplained Pro, then
   support for the SD card slot can be enabled by making the following
   changes to the configuration:

   File Systems:
     CONFIG_FS_FAT=y                   : Enable the FAT file system
     CONFIG_FAT_LCNAMES=y              : Enable upper/lower case 8.3 file names (Optional, see below)
     CONFIG_FAT_LFN=y                  : Enable long file named (Optional, see below)
     CONFIG_FAT_MAXFNAME=32            : Maximum supported file name length

     There are issues related to patents that Microsoft holds on FAT long
     file name technologies.  See the top level NOTICE file for further
     details.

   System Type -> Peripherals:
     CONFIG_SAM34_SPI0=y                : Enable the SAM4L SPI peripheral

   Device Drivers
     CONFIG_SPI=y                      : Enable SPI support
     CONFIG_SPI_EXCHANGE=y             : The exchange() method is supported

     CONFIG_MMCSD=y                    : Enable MMC/SD support
     CONFIG_MMCSD_NSLOTS=1             : Only one MMC/SD card slot
     CONFIG_MMCSD_MULTIBLOCK_LIMIT=0   : Should not need to disable multi-block transfers
     CONFIG_MMCSD_HAVE_CARDDETECT=y    : I/O1 module as a card detect GPIO
     CONFIG_MMCSD_SPI=y                : Use the SPI interface to the MMC/SD card
     CONFIG_MMCSD_SPICLOCK=20000000    : This is a guess for the optimal MMC/SD frequency
     CONFIG_MMCSD_SPIMODE=0            : Mode 0 is required

   Board Selection -> Common Board Options
     CONFIG_NSH_MMCSDSLOTNO=0          : Only one MMC/SD slot, slot 0
     CONFIG_NSH_MMCSDSPIPORTNO=0       : Use CS=0 if the I/O1 is in EXT1, OR
     CONFIG_NSH_MMCSDSPIPORTNO=2       : Use CS=2 if the I/O1 is in EXT2

   Board Selection -> SAM4L Xplained Pro Modules
     CONFIG_SAM4L_XPLAINED_IOMODULE=y      : I/O1 module is connected
     CONFIG_SAM4L_XPLAINED_IOMODULE_EXT1=y : In EXT1, or EXT2
     CONFIG_SAM4L_XPLAINED_IOMODULE_EXT2=y

   Application Configuration -> NSH Library
     CONFIG_NSH_ARCHINIT=y             : Board has architecture-specific initialization

   NOTE: If you enable the I/O1 this configuration with USART0 as the
   console and with the I/O1 module in EXT1, you *must* remove UART
   jumper.  Otherwise, you have lookpack on USART0 and NSH will *not*
   behave very well (since its outgoing prompts also appear as incoming
   commands).

   STATUS:  As of 2013-6-18, this configuration appears completely
   functional.  Testing, however, has been very light.  Example:

     NuttShell (NSH) NuttX-6.28
     nsh> mount -t vfat /dev/mmcsd0 /mnt/stuff
     nsh> ls /mnt/stuff
     /mnt/stuff:
     nsh> echo "This is a test" >/mnt/stuff/atest.txt
     nsh> ls /mnt/stuff
     /mnt/stuff:
      atest.txt
     nsh> cat /mnt/stuff/atest.txt
     This is a test
     nsh>

3. If the OLED1 module is connected to the SAM4L Xplained Pro, then
   support for the OLED display can be enabled by making the following
   changes to the configuration:

   System Type -> Peripherals:
     CONFIG_SAM34_SPI0=y                 : Enable the SAM4L SPI peripheral

   Device Drivers -> SPI
     CONFIG_SPI=y                       : Enable SPI support
     CONFIG_SPI_EXCHANGE=y              : The exchange() method is supported
     CONFIG_SPI_CMDDATA=y               : CMD/DATA support is required

   Device Drivers -> LCDs
     CONFIG_LCD=y                       : Enable LCD support
     CONFIG_LCD_MAXCONTRAST=255         : Maximum contrast value
     CONFIG_LCD_LANDSCAPE=y             : Landscape orientation (see below*)
     CONFIG_LCD_UG2832HSWEG04=y         : Enable support for the OLED
     CONFIG_LCD_SSD1306_SPIMODE=0       : SPI Mode 0
     CONFIG_LCD_SSD1306_SPIMODE=3500000 : Pick an SPI frequency

   Board Selection -> SAM4L Xplained Pro Modules
     CONFIG_SAM4L_XPLAINED_OLED1MODULE=y      : OLED1 module is connected
     CONFIG_SAM4L_XPLAINED_OLED1MODULE_EXT1=y : In EXT1, or EXT2
     CONFIG_SAM4L_XPLAINED_OLED1MODULE_EXT2=y

   The NX graphics subsystem also needs to be configured:

     CONFIG_NX=y                        : Enable graphics support
     CONFIG_NX_LCDDRIVER=y              : Using an LCD driver
     CONFIG_NX_NPLANES=1                : With a single color plane
     CONFIG_NX_WRITEONLY=n              : You can read from the LCD (see below**)
     CONFIG_NX_DISABLE_2BPP=y           : Disable all resolutions except 1BPP
     CONFIG_NX_DISABLE_4BPP=y
     CONFIG_NX_DISABLE_8BPP=y
     CONFIG_NX_DISABLE_16BPP=y
     CONFIG_NX_DISABLE_24BPP=y
     CONFIG_NX_DISABLE_32BPP=y
     CONFIG_NX_PACKEDMSFIRST=y          : LSB packed first (shouldn't matter)
     CONFIG_NXSTART_EXTERNINIT=y        : We have board_graphics_setup()
     CONFIG_NXTK_BORDERWIDTH=2          : Use a small border
     CONFIG_NXTK_DEFAULT_BORDERCOLORS=y : Default border colors
     CONFIG_NXFONTS_CHARBITS=7          : 7-bit fonts
     CONFIG_NXFONT_SANS17X23B=y         : Pick a font (any that will fit)

    * This orientation will put the buttons "above" the LCD.  The
      reverse landscape configuration (CONFIG_LCD_RLANDSCAPE) will
      "flip" the display so that the buttons are "below" the LCD.

   ** The hardware is write only, but the driver maintains a frame buffer
      to support read and read-write-modiry operations on the LCD.
      Reading from the frame buffer is, however, untested.

   Then, in order to use the OLED, you will need to build some kind of
   graphics application or use one of the NuttX graphics examples.
   Here, for example, is the setup for the graphic "Hello, World!"
   example:

     CONFIG_EXAMPLES_NXHELLO=y                : Enables the example
     CONFIG_EXAMPLES_NXHELLO_DEFAULT_COLORS=y : Use default colors (see below *)
     CONFIG_EXAMPLES_NXHELLO_DEFAULT_FONT=y   : Use the default font
     CONFIG_EXAMPLES_NXHELLO_BPP=1            : One bit per pixel
     CONFIG_EXAMPLES_NXHELLO_EXTERNINIT=y     : Special initialization is required.

    * The OLED is monochrome so the only "colors" are black and white.
      The default "colors" will give you while text on a black background.
      You can override the faults it you want black text on a while background.

   NOTE:  One issue that I have seen with the NXHello example when
   running as an NSH command is that it only works the first time.
   So, after you run the 'nxhello' command one time, you will have to
   reset the board before you run it again.

   This is clearly some issue with initializing, un-initializing, and
   then re-initializing. If you want to fix this, patches are quite
   welcome.

4. If the LCD1 module is connected to the SAM4L Xplained Pro, then
   support for the SLCDt can be enabled by making the following
   changes to the configuration:

   System Type -> AT91SAM3/4 Peripheral Support
     CONFIG_SAM34_LCDCA=y

   System Type -> AT91SAM3/4 Clock Configuration
     CONFIG_SAM34_OSC32K=y

   Board Selection -> Board-Specific Options -> SAM4L Xplained Pro Modules
     CONFIG_SAM4L_XPLAINED_SLCD1MODULE=y

   Device Drivers
     CONFIG_LCD=y
     CONFIG_LCD_MAXCONTRAST=63

   Library Routines -> Non-standard Library Support
     CONFIG_LIBC_SLCDCODEC=y

   The SLCD example can be enabled to verify the SLCD:

   Application Configuration -> Examples
     CONFIG_EXAMPLES_SLCD=y
     CONFIG_EXAMPLES_SLCD_DEVNAME="/dev/slcd0"
     CONFIG_EXAMPLES_SLCD_BUFSIZE=64

   Application Configuration -> NSH Library
     CONFIG_NSH_ARCHINIT=y

   NOTE:  In order to use the segment LCD you *must* open the VLCD_A and
   VLCD_BC jumpers or the SLD will not be powered!