README
======
This README file discusses the port of NuttX to the Atmel SAM E70 board from
QMTECH. This board features the ATSAME70N19 Cortex-M7 microcontroller.
Contents
========
- Status/Open Issues
- Serial Console
- SD card
- Automounter
- LEDs and Buttons
- Program FLASH Access
- SPI Slave
- Tickless OS
- Debugging
- Using OpenOCD and GDB to flash via the EDBG chip
- Configurations
Status/Open Issues
==================
2015-11-30: The basic NSH configuration is function with serial console
via the EDBG VCOM and LED and buttons support. SD card slot also appear
to be fully functional.
See also boards/arm/samv7/samv70-xplained/README.txt
Serial Console
==============
The SAME70-QMTECH has no on-board RS-232 drivers so it will be necessary to
use either the VCOM or an external RS-232 driver. Here are some options.
- Arduino Serial Shield: One option is to use an Arduino-compatible
serial shield. This will use the RXD and TXD signals available at pins
0 an 1, respectively, of the Arduino "Digital Low" connector. On the
SAME70-QMTECH board, this corresponds to UART3:
------ ------ ------- ------- --------
Pin on SAME70 Arduino Arduino SAME70
J503 PIO Name Pin Function
------ ------ ------- ------- --------
1 PD28 D0/RX0 0 URXD3
2 PD30 D1/TX0 1 UTXD3
------ ------ ------- ------- --------
In this configuration, an external RS232 driver can also be used
instead of the shield. Simply connext as follows:
--------- -----------
Arduino RS-232
Pin Label Connection
--------- -----------
D0 (RXD) RX
D1 (TXD) TX
GND GND
5VO Vcc
--------- -----------
SD Card
=======
Card Slot
---------
The SAM E70 QMTECH has one standard SD card connector that is connected to
the High Speed Multimedia Card Interface (HSMCI) of the SAM
E70. SD card connector:
------ ----------------- ---------------------
SAME70 SAME70 Shared functionality
Pin Function
------ ----------------- ---------------------
PA30 MCDA0 (DAT0)
PA31 MCDA1 (DAT1)
PA26 MCDA2 (DAT2)
PA27 MCDA3 (DAT3)
PA25 MCCK (CLK) Shield
PA28 MCCDA (CMD)
PD17 Card Detect (C/D) Shield
------ ----------------- ---------------------
Configuration Settings
----------------------
Enabling HSMCI support. The SAME70-QMTECH provides a one, full-size SD memory
card slots. The full size SD card slot connects via HSMCI0. Support for
the SD slots can be enabled with the following settings:
System Type->SAMV7 Peripheral Selection
CONFIG_SAMV7_HSMCI0=y : To enable HSMCI0 support
CONFIG_SAMV7_XDMAC=y : XDMAC is needed by HSMCI0/1
System Type
CONFIG_SAMV7_GPIO_IRQ=y : PIO interrupts needed
CONFIG_SAMV7_GPIOD_IRQ=y : Card detect pin is on PD18
Device Drivers -> MMC/SD Driver Support
CONFIG_MMCSD=y : Enable MMC/SD support
CONFIG_MMSCD_NSLOTS=1 : One slot per driver instance
CONFIG_MMCSD_MULTIBLOCK_DISABLE=y : (REVISIT)
CONFIG_MMCSD_HAVE_CARDDETECT=y : Supports card-detect PIOs
CONFIG_MMCSD_MMCSUPPORT=n : Interferes with some SD cards
CONFIG_MMCSD_SPI=n : No SPI-based MMC/SD support
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
RTOS Features -> Work Queue Support
CONFIG_SCHED_WORKQUEUE=y : Driver needs work queue support
Application Configuration -> NSH Library
CONFIG_NSH_ARCHINIT=y : NSH board-initialization, OR
CONFIG_BOARD_LATE_INITIALIZE=y
Using the SD card
-----------------
1) After booting, the HSCMI device will appear as /dev/mmcsd0.
2) If you try mounting an SD card with nothing in the slot, the mount will
fail:
nsh> mount -t vfat /dev/mmcsd0 /mnt/sd0
nsh: mount: mount failed: 19
NSH can be configured to provide errors as strings instead of
numbers. But in this case, only the error number is reported. The
error numbers can be found in nuttx/include/errno.h:
#define ENODEV 19
#define ENODEV_STR "No such device"
So the mount command is saying that there is no device or, more
correctly, that there is no card in the SD card slot.
3) Inserted the SD card. Then the mount should succeed.
nsh> mount -t vfat /dev/mmcsd0 /mnt/sd0
nsh> ls /mnt/sd1
/mnt/sd1:
atest.txt
nsh> cat /mnt/sd1/atest.txt
This is a test
NOTE: See the next section entitled "Auto-Mounter" for another way
to mount your SD card.
4) Before removing the card, you must umount the file system. This is
equivalent to "ejecting" or "safely removing" the card on Windows: It
flushes any cached data to an SD card and makes the SD card unavailable
to the applications.
nsh> umount -t /mnt/sd0
It is now safe to remove the card. NuttX provides into callbacks
that can be used by an application to automatically unmount the
volume when it is removed. But those callbacks are not used in
these configurations.
Auto-Mounter
============
NuttX implements an auto-mounter than can make working with SD cards
easier. With the auto-mounter, the file system will be automatically
mounted when the SD card is inserted into the HSMCI slot and automatically
unmounted when the SD card is removed.
Here is a sample configuration for the auto-mounter:
File System Configuration
CONFIG_FS_AUTOMOUNTER=y
Board-Specific Options
CONFIG_SAME70QMTECH_HSMCI0_AUTOMOUNT=y
CONFIG_SAME70QMTECH_HSMCI0_AUTOMOUNT_FSTYPE="vfat"
CONFIG_SAME70QMTECH_HSMCI0_AUTOMOUNT_BLKDEV="/dev/mmcsd0"
CONFIG_SAME70QMTECH_HSMCI0_AUTOMOUNT_MOUNTPOINT="/mnt/sdcard"
CONFIG_SAME70QMTECH_HSMCI0_AUTOMOUNT_DDELAY=1000
CONFIG_SAME70QMTECH_HSMCI0_AUTOMOUNT_UDELAY=2000
WARNING: SD cards should never be removed without first unmounting
them. This is to avoid data and possible corruption of the file
system. Certainly this is the case if you are writing to the SD card
at the time of the removal. If you use the SD card for read-only access,
however, then I cannot think of any reason why removing the card without
mounting would be harmful.
LEDs and Buttons
================
LEDs
----
A single LED is available driven by PA14.
This LED is not used by the board port unless CONFIG_ARCH_LEDS is
defined. In that case, the usage by the board port is defined in
include/board.h and src/sam_autoleds.c. The LED is used to encode
OS-related events as follows:
------------------- ----------------------- ------
SYMBOL Meaning LED
------------------- ----------------------- ------
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 if the LED is statically on, NuttX has successfully booted and is,
apparently, running normally. If the LED is flashing at approximately
2Hz, then a fatal error has been detected and the system has halted.
Buttons
-------
SAM E70 QMTECH contains two mechanical buttons. One button is the RESET
button connected to the SAM E70 reset line and the other, PA21, is a generic
user configurable button. When a button is pressed it will drive the I/O
line to GND.
NOTE: There are no pull-up resistors connected to the generic user buttons
so it is necessary to enable the internal pull-up in the SAM E70 to use the
button.
SPI Slave
=========
An interrutp driven SPI slave driver as added on 2015-08-09 but has not
been verified as of this writing. See discussion in include/nuttx/spi/slave.h
and below.
I do not yet have a design that supports SPI slave DMA. And, under
certain, very limited conditions, I think it can be done. Those
certain conditions are:
a) The master does not tie the chip select to ground. The master must
raise chip select at the end of the transfer. Then I do not need to
know the length of the transfer; I can cancel the DMA when the chip
is de-selected.
b) The protocol includes a dummy read after sending the command. This
is very common in SPI device and should not be an issue if it is
specified. This dummy read time provides time to set up the DMA.
So the protocol would be:
i) Master drops the chip select.
ii) Master sends the command which will indicate whether the master
is reading, writing, or exchanging data. The master discards
the garbage return value.
iii) Slave is interrupted when the command word is received. The
SPI device then decodes the command word and setups up the
subsequent DMA.
iv) Master sends a dummy word and discards the return value.
During the bit times to shift the dummy word, the slave has time
to set up the DMA.
v) Master then reads or writes (or exchanges) the data If the DMA
is in place, the transfer should continue normally.
vi) At the end of the data transfer the master raises the chip
select.
c) There are limitations in the word time, i.e., the time between the
interrupt for each word shifted in from the master.
The controller driver will get events after the receipt of each word in
ii), iv), and v). The time between each word will be:
word-time = nbits * bit time + inter-word-gap
So for an 8 bit interface at 20MHz, the words will be received from the
master a 8 * 50nsec = 400 nsec + inter-word-gap. That is the time
during which the dummy word would be shifted and during which we
receive the interrupt for the command word, interpret the command word,
and to set up the DMA for the remaining word transfer. I don't think
that is possible, at least not at 20 MHz.
That is far too fast even for the interrupt driven solution that I have
in place now. It could not work at 20MHz. If we suppose that interrupt
processing is around 1 usec, then an 8 bit interface could not have bit
times more than 125 nsec or 8 KHz. Interrupt handling should be faster
than 1 usec, but not a lot faster. I have not benchmarked it. NuttX
also supports special, zero latency interrupts that could bring the
interrupt time down even more.
Note that we would also have a little more processing time if you used
16-bit SPI word size.
Note also that the interrupt driven approach would have this same basic
performance limitation with the additional disadvantage that:
a) The driver will receive two interrupts per word exchanged:
i) One interrupt will be received when the word is shifted in from
the master (at the end of 8-bit times). This is a data received
interrupt.
ii) And another interrupt when the next words moved to the shift-out
register, freeing up the transmit holding register. This is the
data sent interrupt.
The ii) event should be very soon after the i) event.
Without DMA, the only way to reduce the interrupt rate would be to add
interrupt-level polling to detect the when transmit holding register
is available. That is not really a good idea.
b) It will hog all of the CPU for the duration of the transfer).
Tickless OS
===========
Background
----------
By default, a NuttX configuration uses a periodic timer interrupt that
drives all system timing. The timer is provided by architecture-specific
code that calls into NuttX at a rate controlled by CONFIG_USEC_PER_TICK.
The default value of CONFIG_USEC_PER_TICK is 10000 microseconds which
corresponds to a timer interrupt rate of 100 Hz.
An option is to configure NuttX to operation in a "tickless" mode. Some
limitations of default system timer are, in increasing order of
importance:
- Overhead: Although the CPU usage of the system timer interrupt at 100Hz
is really very low, it is still mostly wasted processing time. One most
timer interrupts, there is really nothing that needs be done other than
incrementing the counter.
- Resolution: Resolution of all system timing is also determined by
CONFIG_USEC_PER_TICK. So nothing that be time with resolution finer than
10 milliseconds be default. To increase this resolution,
CONFIG_USEC_PER_TICK an be reduced. However, then the system timer
interrupts use more of the CPU bandwidth processing useless interrupts.
- Power Usage: But the biggest issue is power usage. When the system is
IDLE, it enters a light, low-power mode (for ARMs, this mode is entered
with the wfi or wfe instructions for example). But each interrupt
awakens the system from this low power mode. Therefore, higher rates
of interrupts cause greater power consumption.
The so-called Tickless OS provides one solution to issue. The basic
concept here is that the periodic, timer interrupt is eliminated and
replaced with a one-shot, interval timer. It becomes event driven
instead of polled: The default system timer is a polled design. On
each interrupt, the NuttX logic checks if it needs to do anything
and, if so, it does it.
Using an interval timer, one can anticipate when the next interesting
OS event will occur, program the interval time and wait for it to fire.
When the interval time fires, then the scheduled activity is performed.
Configuration
-------------
The following configuration options will enable support for the Tickless
OS for the SAMV7 platforms using TC0 channels 0-3 (other timers or
timer channels could be used making the obvious substitutions):
RTOS Features -> Clocks and Timers
CONFIG_SCHED_TICKLESS=y : Configures the RTOS in tickless mode
CONFIG_SCHED_TICKLESS_ALARM=n : (option not implemented)
CONFIG_SCHED_TICKLESS_LIMIT_MAX_SLEEP=y
System Type -> SAMV7 Peripheral Support
CONFIG_SAMV7_TC0=y : Enable TC0 (TC channels 0-3
System Type -> Timer/counter Configuration
CONFIG_SAMV7_ONESHOT=y : Enables one-shot timer wrapper
CONFIG_SAMV7_FREERUN=y : Enabled free-running timer wrapper
CONFIG_SAMV7_TICKLESS_ONESHOT=0 : Selects TC0 channel 0 for the one-shot
CONFIG_SAMV7_TICKLESS_FREERUN=1 : Selects TC0 channel 1 for the free-
: running timer
The resolution of the clock is provided by the CONFIG_USEC_PER_TICK
setting in the configuration file.
NOTE: In most cases, the slow clock will be used as the timer/counter
input. The SAME70-Xplained board has pads for a 32.768KHz crystal,
however, the boad ships with that position unpopulated. So, be default
this will probably end up using the slow RC oscillator which will give
you very bad timing.
If you add a crystal to your board, you can select to use it with the
definition BOARD_HAVE_SLOWXTAL in the boards/arm/samv7/same70-qmtech/board.h
file.
The slow clock has a resolution of about 30.518 microseconds. Ideally,
the value of CONFIG_USEC_PER_TICK should be the exact clock resolution.
Otherwise there will be cumulative timing inaccuracies. But a choice
choice of:
CONFIG_USEC_PER_TICK=31
will have an error of 0.6% and will have inaccuracies that will
effect the time due to long term error build-up.
Using the slow clock input, the Tickless support is functional,
however, there are inaccuracies in delays. For example,
nsh> sleep 10
results in a delay of maybe 5.4 seconds. But the timing accuracy is
correct if all competing uses of the interval timer are disabled (mostly
from the high priority work queue). Therefore, I conclude that this
inaccuracy is due to the inaccuracies in the representation of the clock
rate. 30.518 usec cannot be represented accurately. Each timing
calculation results in a small error. When the interval timer is very
busy, long delays will be divided into many small pieces and each small
piece has a large error in the calculation. The cumulative error is the
cause of the problem.
Solution: The same70-qmtech/src/sam_boot.c file has additional logic
to enable the programmable clock PCK6 as a clock source for the
timer/counters if the Tickless mode is selected. The ideal frequency
would be:
frequency = 1,000,000 / CONFIG_USEC_PER_TICK
The main crystal is selected as the frequency source. The maximum
prescaler value is 256 so the minimum frequency is 46,875 Hz which
corresponds to a period of 21.3 microseconds. A value of
CONFIG_USEC_PER_TICK=20, or 50KHz, would give an exact solution with
a divider of 240.
SAME70 Timer Usage
------------------
This current implementation uses two timers: A one-shot timer to
provide the timed events and a free running timer to provide the current
time. Since timers are a limited resource, that could be an issue on
some systems.
We could do the job with a single timer if we were to keep the single
timer in a free-running at all times. The SAME70 timer/counters have
16-bit counters with the capability to generate a compare interrupt when
the timer matches a compare value but also to continue counting without
stopping (giving another, different interrupt when the timer rolls over
from 0xffff to zero). So we could potentially just set the compare at
the number of ticks you want PLUS the current value of timer. Then you
could have both with a single timer: An interval timer and a free-
running counter with the same timer! In this case, you would want to
to set CONFIG_SCHED_TICKLESS_ALARM in the NuttX configuration.
Patches are welcome!
Debugging
=========
EDBG
----
The on-board EDBG appears to work only with Atmel Studio. You can however,
simply connect a SAM-ICE or J-Link to the JTAG/SWD connector on the board
and that works great. The only tricky thing is getting the correct
orientation of the JTAG connection.
J-Link/JTAG
-----------
I have been using Atmel Studio to write code to flash then I use the Segger
J-Link GDB server to debug. I have been using the 'Device Programming' I
available under the Atmel Studio 'Tool' menu. I have to disconnect the
SAM-ICE while programming with the EDBG. I am sure that you could come up
with a GDB server-only solution if you wanted.
I run GDB like this from the directory containing the NuttX ELF file:
arm-none-eabi-gdb
(gdb) target remote localhost:2331
(gdb) mon reset
(gdb) file nuttx
(gdb) ... start debugging ...
OpenOCD/EDBG
------------
Current OpenOCD also works with SAME70-QMTECH via EDBG, but I have not
used OpenOCD with the board.
SAM-BA
------
SAM-BA is another option. With SAM-BA, you can load code into FLASH over
a serial port or USB connection by booting into the ROM bootloader.
CMSIS-DAP Programmer
--------------------
Another useful tool for CMSIS-DAP programmer (formerly Atmel EDBG
programmer) available at:
https://github.com/ataradov/edbg
This is a simple command line utility for programming ARM-based MCUs
(currently only Atmel) though CMSIS-DAP SWD interface. It works on Linux,
macOS and Windows. Very useful to around especially if you have the
following issue:
Booting to FLASH or the ROM Bootloader
--------------------------------------
If you use EDBG or JTAG to load code into FLASH, you may be puzzled why
the code does not run. It may be that you are booting into the ROM
bootloader instead of FLASH. That can be fixed by modifying the SAME70's
GPNVM bits.
If your SAME70 is booting in ROM by default, the GPNVM bits will probably
looking something like:
$ edbg.exe -F r,:, -t atmel_cm7
GPNVM Bits: 0x40
Where bit 1 = 0 boots into the ROM bootloader and bit 1 = 1 boots into
FLASH. You want:
$ edbg.exe -F r,:, -t atmel_cm7
GPNVM Bits: 0x42
If you are trying to use SAM-BA, you might have the opposity problem:
The board might be booting into FLASH when you need it to boot into the
ROM bootloader.
That GPNVM bit can be changed using CMSIS-DAP programmer, Atmel studio, or
using this OpenOCD setup:
atsamv gpnvm [('clr'|'set'|'show') bitnum]
Without arguments, shows all bits in the gpnvm register.
Otherwise, clears, sets, or shows one General Purpose Non-Volatile
Memory (gpnvm) bit.
Perhaps SAM-BA supports a way to do this as well???
Using OpenOCD and GDB to flash via the EDBG chip
================================================
Building OpenOCD under Cygwin:
Refer to boards/olimex-lpc1766stk/README.txt
Installing OpenOCD in Linux (but see note below):
sudo apt-get install openocd
NOTE: At the time of writing installing the above openocd package from
the distribution (Ubuntu 14.04) was not enough to get the latest openocd
version supporting the SAME70 Xplained.
The code was obtained from the OpenOCD git repository, available at
https://github.com/ntfreak/openocd.
git clone https://github.com/ntfreak/openocd.git
Then follow the directions of the "Building OpenOCD" section of their README,
but be sure to configure including the CMSIS-DAP interface:
./bootstrap
./configure --enable-cmsis-dap
make
sudo make install
If your configure step fails, you might be missing some dependencies, i.e.:
sudo apt-get install libhidapi-dev
Helper Scripts.
OpenOCD requires a configuration file. I keep the one I used last here:
boards/arm/samv7/same70-qmtech/tools/atmel_same70_qmtech.cfg
However, the "correct" configuration script to use with OpenOCD may
change as the features of OpenOCD evolve. So you should at least
compare that atmel_same70_qmtech.cfg file with configuration files in
/usr/share/openocd/scripts. As of this writing, the configuration
files of interest were:
/usr/share/openocd/scripts/interface/cmsis-dap.cfg
/usr/share/openocd/scripts/board/atmel_same70_qmtech.cfg
/usr/share/openocd/scripts/target/atsamv.cfg
There is also a script on the tools/ directory that I use to start
the OpenOCD daemon on my system called oocd.sh. That script will
probably require some modifications to work in another environment:
- Possibly the value of OPENOCD_PATH and TARGET_PATH
- It assumes that the correct script to use is the one at
boards/arm/samv7/same70-qmtech/tools/atmel_same70_qmtech.cfg
Starting OpenOCD
Then you should be able to start the OpenOCD daemon like:
boards/arm/samv7/same70-qmtech/tools/oocd.sh $PWD
Connecting GDB
Once the OpenOCD daemon has been started, you can connect to it via
GDB using the following GDB command:
arm-nuttx-elf-gdb
(gdb) target remote localhost:3333
NOTE: The name of your GDB program may differ. For example, with the
CodeSourcery toolchain, the ARM GDB would be called arm-none-eabi-gdb.
After starting GDB, you can load the NuttX ELF file:
(gdb) symbol-file nuttx
(gdb) monitor reset
(gdb) monitor halt
(gdb) load nuttx
NOTES:
1. Loading the symbol-file is only useful if you have built NuttX to
include debug symbols (by setting CONFIG_DEBUG_SYMBOLS=y in the
.config file).
2. The MCU must be halted prior to loading code using 'mon reset'
as described below.
OpenOCD will support several special 'monitor' commands. These
GDB commands will send comments to the OpenOCD monitor. Here
are a couple that you will need to use:
(gdb) monitor reset
(gdb) monitor halt
NOTES:
1. The MCU must be halted using 'mon halt' prior to loading code.
2. Reset will restart the processor after loading code.
3. The 'monitor' command can be abbreviated as just 'mon'.
Configurations
==============
Information Common to All Configurations
----------------------------------------
Each SAME70-QMTECH configuration is maintained in a sub-directory and
can be selected as follow:
tools/configure.sh same70-qmtech:<subdir>
Before building, make sure that the PATH environment variable include 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 oldconfig
make
The <subdir> that is provided above as an argument to the tools/configure.sh
must be is one of the following.
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.
2. Unless stated otherwise, all configurations generate console
output on USART1 (the EDBG VCOM)
NOTE: When USART1 is used, the pin PB4 is reconfigured. Normally, PB4
is TDI. When it is reconfigured for use with USART1, the capability to
debug is lost! If you plan to debug you should most certainly not use
USART1. UART3 might be a good option (the Arduino RXD/TXD):
-CONFIG_SAMV7_USART1=y
-CONFIG_USART1_SERIALDRIVER=y
-CONFIG_USART1_SERIAL_CONSOLE=y
-CONFIG_USART1_RXBUFSIZE=256
-CONFIG_USART1_TXBUFSIZE=256
-CONFIG_USART1_BAUD=115200
-CONFIG_USART1_BITS=8
-CONFIG_USART1_PARITY=0
-CONFIG_USART1_2STOP=0
+CONFIG_SAMV7_UART3=y
+CONFIG_UART3_SERIAL_CONSOLE=y
+CONFIG_UART3_RXBUFSIZE=256
+CONFIG_UART3_TXBUFSIZE=256
+CONFIG_UART3_BAUD=115200
+CONFIG_UART3_BITS=8
+CONFIG_UART3_PARITY=0
+CONFIG_UART3_2STOP=0
UART3 is not the default because (1) the placement of the RJ-45 connector
makes it difficult to install Arduino shield cards and (2) the Arduino
connectors are not populated on the board as it comes from the factory.
3. All of these configurations are set up to build under Windows using the
"GNU Tools for ARM Embedded Processors" that is maintained by ARM
(unless stated otherwise in the description of the configuration).
https://developer.arm.com/open-source/gnu-toolchain/gnu-rm
That toolchain selection can easily be reconfigured using
'make menuconfig'. Here are the relevant current settings:
Build Setup:
CONFIG_HOST_WINDOWS=y : Window environment
CONFIG_WINDOWS_CYGWIN=y : Cywin under Windows
System Type -> Toolchain:
CONFIG_ARMV7M_TOOLCHAIN_GNU_EABIW=y : GNU ARM EABI toolchain
NOTE: As of this writing, there are issues with using this tool at
the -Os level of optimization. This has not been proven to be a
compiler issue (as least not one that might not be fixed with a
well placed volatile qualifier). However, in any event, it is
recommend that you use not more that -O2 optimization.
Configuration sub-directories
-----------------------------
adc
This is a basic nsh configuration (se below) with added example for
ADC (AFEC) driver. Data can be read through channel AFE0_AD0 by
running application "adc" in NuttShell.
The ADC is triggered by Timer/counter at 1 kHz frequency and uses
DMA to transfer samples. Number of transfered samples can be set
by configuring CONFIG_SAMV7_AFEC_DMASAMPLES.
nsh:
Configures the NuttShell (nsh) located at examples/nsh. There are two
very similar NSH configurations:
- nsh. This configuration is focused on low level, command-line
driver testing. It has no network.
- netnsh. This configuration is focused on network testing and
has only limited command support.
NOTES:
1. The serial console is configured by default for use with the EDBG VCOM
(USART1). You will need to reconfigure if you will to use a different
U[S]ART. See "Information Common to All Configurations" above.
2. Default stack sizes are large and should really be tuned to reduce
the RAM footprint:
CONFIG_ARCH_INTERRUPTSTACK=2048
CONFIG_IDLETHREAD_STACKSIZE=1024
CONFIG_INIT_STACKSIZE=2048
CONFIG_PTHREAD_STACK_DEFAULT=2048
... and others ...
3. NSH built-in applications are supported.
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
4. Support for HSMCI is built-in by default. The SAME70-QMTECH provides
one full-size SD memory card slot. Refer to the section entitled
"SD card" for configuration-related information.
See "Open Issues" above for issues related to HSMCI.
The auto-mounter is not enabled. See the section above entitled
"Auto-Mounter".
5. Performance-related Configuration settings:
CONFIG_ARMV7M_ICACHE=y : Instruction cache is enabled
CONFIG_ARMV7M_DCACHE=y : Data cache is enabled
CONFIG_ARMV7M_DCACHE_WRITETHROUGH=n : Write back mode
CONFIG_ARCH_FPU=y : H/W floating point support is enabled
CONFIG_ARCH_DPFPU=y : 64-bit H/W floating point support is enabled
# CONFIG_ARMV7M_ITCM is not set : Support not yet in place
# CONFIG_ARMV7M_DTCM is not set : Support not yet in place
Stack sizes are also large to simplify the bring-up and should be
tuned for better memory usages.
STATUS:
2015-03-28: HSMCI TX DMA is disabled. There are some issues with the TX
DMA that need to be corrected.
mcuboot-loader:
This configuration exercises the port of MCUboot loader to NuttX.
In this configuration both primary, secondary and scratch partitions are
mapped into the internal flash.
Relevant configuration settings:
CONFIG_BOARD_LATE_INITIALIZE=y
CONFIG_BOOT_MCUBOOT=y
CONFIG_MCUBOOT_BOOTLOADER=y
CONFIG_MCUBOOT_ENABLE_LOGGING=y
CONFIG_SAMV7_FORMAT_MCUBOOT=y
CONFIG_INIT_ENTRYPOINT="mcuboot_loader_main"
mcuboot-confirm:
This configuration exercises the MCUboot compatible application slot
confirm example.
Generate signed binaries for MCUboot compatible application:
./apps/boot/mcuboot/mcuboot/scripts/imgtool.py sign \
--key apps/boot/mcuboot/mcuboot/root-rsa-2048.pem --align 8 \
--version 1.0.0 --header-size 0x200 --pad-header --slot-size 0xe0000 \
nuttx/nuttx.bin signed_app_1_0_0.bin
Relevant configuration settings:
CONFIG_BOARD_LATE_INITIALIZE=y
CONFIG_BOOT_MCUBOOT=y
CONFIG_MCUBOOT_SLOT_CONFIRM_EXAMPLE=y
CONFIG_SAMV7_FORMAT_MCUBOOT=y
CONFIG_INIT_ENTRYPOINT="mcuboot_confirm_main"
