README.txt
==========
This directory holds a port of NuttX to the NXP/Freescale Sabre board
featuring the iMX 6Quad CPU.
Contents
========
- Status
- Platform Features
- Serial Console
- LEDs and Buttons
- Using U-Boot to Run NuttX
- Configurations
Status
======
2016-02-28: The i.MX6Q port is just beginning. A few files have been
populated with the port is a long way from being complete or even ready to
begin any kind of testing.
2016-03-12: The i.MX6Q port is code complete including initial
implementation of logic needed for CONFIG_SMP=y . There is no clock
configuration logic. This is probably not an issue if we are loaded into
SDRAM by a bootloader (because we cannot change the clocking anyway in
that case).
There is a lot of testing that could be done but, unfortunately, I still
have no i.MX6 hardware to test on.
2016-03-28: I now have a used MCIMX6Q-SDB which is similar to the target
configuration described below except that it does not have the 10.1" LVDS
display. Next step: Figure out how to run a copy of NuttX using U-Boot.
Platform Features
=================
Processor:
- i.MX 6Quad or 6DualLite 1 GHz ARM Cortex-A9 processor
Memory/storage:
- 1 GB DDR3 SDRAM up to 533 MHz (1066 MTPS) memory
- 8 GB eMMC flash
- 4 MB SPI NOR flash
Display:
- 10.1" 1024 x 768 LVDS display with integrated P-cap sensing
- HDMI connector
- LVDS connector (for optional second display)
- LCD expansion connector (parallel, 24-bit)
- EPDC expansion connector (for 6DualLite only)
- MIPI DSI connector (two data lanes, 1 GHz each)
User Interface:
- 10.1" capacitive multitouch display
- Buttons: power, reset, volume
Power Management:
- Proprietary PF0100 PMIC
Audio:
- Audio codec
- 2x digital microphones
- 2x 3.5 mm audio ports
- Dual 1 watt speakers
Expansion Connector:
- Camera MIPI CSI port
- I2C, SPI signals
Connectivity:
- 2x full-size SD/MMC card slots
- 7-pin SATA data connector
- 10/100/1000 Ethernet port
- 1x USB 2.0 OTG port (micro USB)
Debug:
- JTAG connector (20-pin)
- 1x Serial-to-USB connector (for JTAG)
OS Support:
- Linux<75> and Android<69> from our company
- Others supported via third party (QNX, Windows Embedded)
Tools Support:
- Manufacturing tool from our company
- IOMUX tool from our company
- Lauterbach, ARM (DS-5), IAR and Macraigor
Additional Features:
- Proprietary 3-axis accelerometer
- Proprietary 3D magnetometer
- Ambient light sensor
- GPS receiver module
- 2x 5MP cameras
- Battery charger
- Battery connectors (battery not included)
Serial Console
==============
A DEBUG VCOM is available MICRO USB AB 5 J509. This corresponds to UART1
from the i.MX6. UART1 connects to J509 via the CSIO_DAT10 and CSIO_DAT11
pins
Configurations
==============
Information Common to All Configurations
----------------------------------------
Each Sabre-6Quad configuration is maintained in a sub-directory and
can be selected as follow:
cd tools
./configure.sh sabre-6quad/<subdir>
cd -
. ./setenv.sh
Before sourcing the setenv.sh file above, you should examine it and perform
edits as necessary so that TOOLCHAIN_BIN is 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 UART1 which is a available to the host PC from the USB
micro AB as a VCOM part.
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://launchpad.net/gcc-arm-embedded
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
LEDs and Buttons
----------------
LEDs
----
A single LED is available driven GPIO1_IO02. On the schematic this is
USR_DEF_RED_LED signal to pin T1 (GPIO_2). This signal is shared with
KEY_ROW6 (ALT2). A low value illuminates the LED.
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
-------
Using U-Boot to Run NuttX
-------------------------
The MCIMX6Q-SDB comes with a 8GB SD card containing the U-Boot and Android.
You simply put the SD card in the SD card slot SD3 (on the bottom of the
board next to the HDMI connect) and Android will boot.
But we need some other way to boot NuttX. Here are some things that I have
experimented with.
Building U-Boot (Attempt #1)
----------------------------
I have been unsuccessful getting building a working version of u-boot from
scratch. It builds, but it does not run. Here are the things I did:
1. Get a copy of the u-boot i.MX6 code via:
https://github.com/boundarydevices/u-boot-imx6/tree/production
or
$ git clone git://git.denx.de/u-boot.git
2. Build U-Boot for the i.MX6Q Sabre using the following steps. This
assumes that you have the path to your arm-none-eabi- toolchain at the
beginning of your PATH variable:
$ cd u-boot
$ export ARCH=arm
$ export CROSS_COMPILE=arm-none-eabi-
$ make mx6qsabresd_config
$ make
This should create a number of files, including u-boot.imx
3. Format an SD card
Create a FAT16 partition at an offset of about 1MB into the SD card.
This is where we will put nuttx.bin.
4. Put U-Boot on SD. U-boot should reside at offset 1024B of your SD
card. To put it there, do:
$ dd if=u-boot.imx of=/dev/<your-sd-card> bs=1k seek=1
$ sync
Your SD card device is typically something in /dev/sd<X> or
/dev/mmcblk<X>. Note that you need write permissions on the SD card
for the command to succeed, so you might need to su - as root, or use
sudo, or do a chmod a+w as root on the SD card device node to grant
permissions to users.
Using the Other SD Card Slot (Attempt #2)
-----------------------------------------
Another option is to use the version u-boot that came on the 8GB but put
NuttX on another SD card inserted in the other SD card slot at the opposite
corner of the board.
To make a long story short: This doesn't work. As far as I can tell,
U-Boot does not support any other other SC card except for mmc 2 with is the
boot SD card slot.
Replace Boot SD Card (Attempt #3)
---------------------------------
What if you remove the SD card after U-boot has booted, then then insert
another SD card containing the nuttx.bin image?
1. Build nuttx.bin and copy it only a FAT formated SD card. Insert the SD
card containing NuttX into the "other" SD card slot. Insert the 8GB SD
card with U-boot already on it in the normal, boot SD card slot.
2. Connect the VCOM port using the USB port next to the boot SD card slot.
3. Start a console at 11500 8N1 on the VCOM port
4. Power up the board with the 8GB SD card in place. U-Boot will start and
countdown before starting Linux. Press enter to break into U-Boot before
Linux is started.
5. Remove the 8GB U-Boot SD card; insert in its place.
6. Rescan the SD card:
MX6Q SABRESD U-Boot > mmc dev 2
mmc2 is current device
MX6Q SABRESD U-Boot > mmc rescan
MX6Q SABRESD U-Boot > fatls mmc 2
system volume information/
87260 nuttx.bin
1 file(s), 1 dir(s)
7. Then we can boot NuttX off the rescanned SD card:
MX6Q SABRESD U-Boot > fatload mmc 2 0x20010000 nuttx.bin
reading nuttx.bin
87260 bytes read
MX6Q SABRESD U-Boot > go 0x2001040
## Starting application at 0x02001040 ...
MX6Q SABRESD U-Boot >
That seems to work okay and this is more than enough of this kind of
thing for a day.
Configuration sub-directories
-----------------------------
nsh
---
This is a NuttShell (NSH) configuration that uses the NSH library
at apps/nshlib with the start logic at apps/examples/nsh.
NOTES:
