SAM3U-EK

This documentation discusses issues unique to NuttX configurations for the Atmel SAM3U-EK development board featuring the ATAM3U. This board features the ATSAM3U4E MCU running at 96MHz.

AtmelStudio 6.1

You can use AtmelStudio6.1 to load and debug code.

  • To load code:

    Tools -> Device Programming

    Configure the debugger and chip and you are in business.

  • To Debug Code:

    File -> Open -> Open Object File for Debugging

    Select the project name, the full path to the NuttX object (called just nuttx with no extension), and chip. Take the time to resolve all of the source file linkages or else you will not have source level debug!

LEDs

The SAM3U-EK board has four LEDs labeled LD1, LD2, LD3 and LD4 on the the board. Usage of these LEDs is defined in include/board.h and src/up_leds.c. They are encoded as follows:

SYMBOL

Meaning

LED0

LED1

LED2

LED_STARTED

NuttX has been started

OFF

OFF

OFF

LED_HEAPALLOCATE

Heap has been allocated

OFF

OFF

ON

LED_IRQSENABLED

Interrupts enabled

OFF

ON

OFF

LED_STACKCREATED

Idle stack created

OFF

ON

ON

LED_INIRQ

In an interrupt (note 2)

N/C

FLASH

N/C

LED_SIGNAL

In a signal handler (note 3)

N/C

N/C

FLASH

LED_ASSERTION

An assertion failed

FLASH

N/C

N/C

LED_PANIC

The system has crashed

FLASH

N/C

N/C

Note

If LED1 and LED2 are statically on, then NuttX probably failed to boot and these LEDs will give you some indication of where the failure was

Note

The normal state is LED0=OFF, LED2=ON and LED1 faintly glowing. This faint glow is because of timer interrupts that result in the LED being illuminated on a small proportion of the time.

Note

LED2 may also flicker normally if signals are processed.

Serial Console

By default, all of these configurations use UART0 for the NuttX serial console. UART0 corresponds to the DB-9 connector labelled “UART”. This is a male connector and will require a female-to-female, NUL modem cable to connect to a PC.

An alternate is USART1 which connects to the other DB-9 connector labeled “USART”. USART1 is not enabled by default unless specifically noted otherwise in the configuration description. A NUL modem cable must be used with the port as well.

Note

One of the USART1 pins is shared with the audio CODEC. The audio CODEC cannot be used of USART1 is enabled.

By default serial console is configured for 115000, 8-bit, 1 stop bit, and no parity.

SAM3U-EK-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_CORTEXM3=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_SAM3U

    • CONFIG_ARCH_CHIP_ATSAM3U4

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

    • CONFIG_ARCH_BOARD=sam3u:ek (for the SAM3U-EK development board)

  • CONFIG_ARCH_BOARD_name: For use in C code

    • CONFIG_ARCH_BOARD_SAM3UEK=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=0x0000c000 (48Kb)

  • 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:

  • CONFIG_SAM34_RTC: Real Time Clock

  • CONFIG_SAM34_RTT: Real Time Timer

  • CONFIG_SAM34_WDT: Watchdog Timer

  • CONFIG_SAM34_UART0: UART 0

  • CONFIG_SAM34_SMC: Static Memory Controller

  • CONFIG_SAM34_USART0: USART 0

  • CONFIG_SAM34_USART1: USART 1

  • CONFIG_SAM34_USART2: USART 2

  • CONFIG_SAM34_USART3: USART 3

  • CONFIG_SAM34_HSMCI: High Speed Multimedia Card Interface

  • CONFIG_SAM34_TWI0: Two-Wire Interface 0

  • CONFIG_SAM34_TWI1: Two-Wire Interface 1

  • CONFIG_SAM34_SPI0: Serial Peripheral Interface

  • CONFIG_SAM34_SSC: Synchronous Serial Controller

  • CONFIG_SAM34_TC0: Timer Counter 0

  • CONFIG_SAM34_TC1: Timer Counter 1

  • CONFIG_SAM34_TC2: Timer Counter 2

  • CONFIG_SAM34_PWM: Pulse Width Modulation Controller

  • CONFIG_SAM34_ADC12B: 12-bit ADC Controller

  • CONFIG_SAM34_ADC: 10-bit ADC Controller

  • CONFIG_SAM34_DMAC0: DMA Controller

  • CONFIG_SAM34_UDPHS: USB Device High Speed

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

  • CONFIG_SAM34_NAND: NAND memory

SAM3U 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.

  • 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

LCD Options. Other than the standard LCD configuration options (see boards/README.txt), the SAM3U-EK driver also supports:

  • CONFIG_LCD_PORTRAIT: Present the display in the standard 240x320 “Portrait” orientation. Default: The display is rotated to support a 320x240 “Landscape” orientation.

Configurations

Each SAM3U-EK configuration is maintained in a sub-directory and can be selected as follows:

$ tools/configure.sh sam3u-ek:<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.

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

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

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

  2. Unless stated otherwise, all configurations generate console output on UART0 (J3).

  3. 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

  4. All of these configurations use the older, OABI, buildroot toolchain (unless stated otherwise in the description of the configuration). That toolchain selection can easily be reconfigured using make menuconfig. Here are the relevant current settings:

    Build Setup:

    • CONFIG_HOST_LINUX=y``: Linux or other pure POSIX invironment (including Cygwin)

    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, for example, 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

    Library Routines ->

    • CONFIG_ARCH_SIZET_LONG=n: size_t is an unsigned int, not long

    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

    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 called “GNU Toolchain Options” above.

knsh

This is identical to the nsh configuration below except that NuttX is built as a kernel-mode, monolithic module and the user applications are built separately. It is recommends to use a special make command; not just make but make with the following two arguments:

$ make pass1 pass2

In the normal case (just make), make will attempt to build both user- and kernel-mode blobs more or less interleaved. This actual works! However, for me it is very confusing so I prefer the above make command: Make the user-space binaries first (pass1), then make the kernel-space binaries (pass2)

  1. At the end of the build, there will be several files in the top-level NuttX build directory:

    PASS1:

    • nuttx_user.elf: The pass1 user-space ELF file

    • nuttx_user.hex: The pass1 Intel HEX format file (selected in defconfig)

    • User.map: Symbols in the user-space ELF file

    PASS2:

    • nuttx: The pass2 kernel-space ELF file

    • nuttx.hex: The pass2 Intel HEX file (selected in defconfig)

    • System.map: Symbols in the kernel-space ELF file

    The J-Link programmer will accept files in .hex, .mot, .srec, and .bin formats.

  2. Combining .hex files. If you plan to use the .hex files with your debugger or FLASH utility, then you may need to combine the two hex files into a single .hex file. Here is how you can do that.

    1. The tail of the nuttx.hex file should look something like this (with my comments added):

      $ tail nuttx.hex
# 00, data records
...
:10 9DC0 00 01000000000800006400020100001F0004
:10 9DD0 00 3B005A0078009700B500D400F300110151
:08 9DE0 00 30014E016D0100008D
# 05, Start Linear Address Record
:04 0000 05 0800 0419 D2
# 01, End Of File record
:00 0000 01 FF

      Use an editor such as vi to remove the 05 and 01 records.

    2. The ‘head’ of the nuttx_user.hex file should look something like this (again with my comments added):

      $ head nuttx_user.hex
# 04, Extended Linear Address Record
:02 0000 04 0801 F1
# 00, data records
:10 8000 00 BD89 01084C800108C8110208D01102087E
:10 8010 00 0010 00201C1000201C1000203C16002026
:10 8020 00 4D80 01085D80010869800108ED83010829
...

      Nothing needs to be done here. The nuttx_user.hex file should be fine.

    3. Combine the edited nuttx.hex and un-edited nuttx_user.hex file to produce a single combined hex file:

      $ cat nuttx.hex nuttx_user.hex > combined.hex

      Then use the combined.hex file with the to write the FLASH image. If you do this a lot, you will probably want to invest a little time to develop a tool to automate these steps.

nsh

Configures the NuttShell (nsh) located at examples/nsh. The Configuration enables both the serial and telnetd NSH interfaces.

  1. NSH built-in applications are supported. However, there are no built-in applications built with the default configuration.

    Binary Formats:

    • CONFIG_BUILTIN=y: Enable support for built-in programs

    Application Configuration:

    • CONFIG_NSH_BUILTIN_APPS=y: Enable starting apps from NSH command line

  2. This configuration has been used for verifying the touchscreen on on the SAM3U-EK LCD. With these modifications, you can include the touchscreen test program at apps/examples/touchscreen as an NSH built-in application. You can enable the touchscreen and test by modifying the default configuration in the following ways:

    Device Drivers

    • CONFIG_SPI=y: Enable SPI support

    • CONFIG_SPI_EXCHANGE=y: The exchange() method is supported

    • CONFIG_INPUT=y: Enable support for input devices

    • CONFIG_INPUT_ADS7843E=y: Enable support for the XPT2046

    • CONFIG_ADS7843E_SPIDEV=2: Use SPI CS 2 for communication

    • CONFIG_ADS7843E_SPIMODE=0: Use SPI mode 0

    • CONFIG_ADS7843E_FREQUENCY=1000000: SPI BAUD 1MHz

    • CONFIG_ADS7843E_SWAPXY=y: If landscpe orientation

    • CONFIG_ADS7843E_THRESHX=51: These will probably need to be tuned

    • CONFIG_ADS7843E_THRESHY=39

    System Type -> Peripherals:

    • CONFIG_SAM34_SPI0=y: Enable support for SPI

    System Type:

    • CONFIG_SAM34_GPIO_IRQ=y: GPIO interrupt support

    • CONFIG_SAM34_GPIOA_IRQ=y: Enable GPIO interrupts from port A

    Library Support:

    • CONFIG_SCHED_WORKQUEUE=y: Work queue support required

    Application Configuration:

    • CONFIG_EXAMPLES_TOUCHSCREEN=y: Enable the touchscreen built-int test

    Defaults should be okay for related touchscreen settings. Touchscreen debug output on UART0 can be enabled with:

    Build Setup:

    • CONFIG_DEBUG_FEATURES=y: Enable debug features

    • CONFIG_DEBUG_INFO=y: Enable verbose debug output

    • CONFIG_DEBUG_INPUT=y: Enable debug output from input devices

  3. Enabling HSMCI support. The SAM3U-KE provides a an SD memory card slot. Support for the SD slot can be enabled with the following settings:

    System Type->ATSAM3/4 Peripheral Support

    • CONFIG_SAM34_HSMCI=y: Enable HSMCI support

    • CONFIG_SAM34_DMAC0=y: DMAC support is needed by HSMCI

    System Type

    • CONFIG_SAM34_GPIO_IRQ=y: PIO interrupts needed

    • CONFIG_SAM34_GPIOA_IRQ=y: Card detect pin is on PIOA

    Device Drivers -> MMC/SD Driver Support

    • CONFIG_MMCSD=y: Enable MMC/SD support

    • CONFIG_MMSCD_NSLOTS=1: One slot per driver instance

    • CONFIG_MMCSD_HAVE_CARDDETECT=y: Supports card-detect PIOs

    • CONFIG_MMCSD_SDIO=y: SDIO-based MMC/SD support

    • CONFIG_SDIO_DMA=y: Use SDIO DMA

    • CONFIG_SDIO_BLOCKSETUP=y: Needs to know block sizes

    Library Routines

    • CONFIG_SCHED_WORKQUEUE=y: Driver needs work queue support

    Application Configuration -> NSH Library

    • CONFIG_NSH_ARCHINIT=y: NSH board-initialization

Warning

  • 2013-6-28: The touchscreen is functional.

  • 2013-6-29: Hmmm… but there appear to be conditions when the touchscreen driver locks up. Looks like some issue with managing the interrupts.

  • 2013-6-30: Those lock-ups appear to be due to poorly placed debug output statements. If you do not enable debug output, the touchscreen is rock-solid.

  • 2013-8-10: Added the comments above above enabling HSMCI memory card support and verified that the configuration builds without error. However, that configuration has not yet been tested (and is may even be incomplete).

nx

Configures to use examples/nx using the HX834x LCD hardware on the SAM3U-EK development board.

nxwm

This is a special configuration setup for the NxWM window manager UnitTest. It includes support for both the HX834x LCD and the ADS7843E touchscreen controller on board the SAM3U-EK board.

The NxWM window manager is a tiny window manager tailored for use with smaller LCDs. It supports a toolchain, a start window, and multiple application windows. However, to make the best use of the visible LCD space, only one application window is visible at at time.

The NxWM window manager can be found at apps/graphics/NxWidgets/nxwm.

The NxWM unit test can be found at apps/graphics/NxWidgets/UnitTests/nxwm.

Warning

  1. 2013-6-28: Created the configuration but have not yet done anything with it.

  2. 2013-6-29: Various changes to get a clean build of this configuration. Still untested.

  3. 20113-6-30: I cannot load this program using AtmelStudio6.1. The total size with DEBUG on is 138.9 KB. I have verified that the first 128KB may have been written correctly, but then the code above 128KB wraps and overwrites the code at the beginning of FLASH, trashing the FLASH images.

    Bottom line: Still untested.