Digi International Linux BSP ConnectCore 6 Reference Manual
Digi ConnectCore 6 is an advanced system-on-module (SOM) powered by NXP i.MX 6Solo/DualLite applications processors. It features high-performance graphics, multimedia, and industrial connectivity options. Ideal for industrial IoT and M2M applications, it delivers a scalable and reliable solution for various industries, including healthcare, transportation, energy, and manufacturing.
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ConnectCore 6
®
Linux BSP
Reference Manual
90001403_A
Revision Record
Revision Date (MM/DD/YY) Description
A
05/22/2014
Preliminary draft release
Copyright and Trademarks
© 2014 Digi International Inc. All rights reserved.
Digi, Digi International, the Digi logo, and ConnectCore 6
®
are trademarks or registered trademarks in the United States and other countries worldwide. All other trademarks mentioned in this document are the property of their respective owners.
Information in this document is subject to change without notice and does not represent a commitment on the part of Digi International. Digi provides this document “as is,” without warranty of any kind, expressed or implied, including, but not limited to, the implied warranties of fitness or merchantability for a particular purpose. Digi may make improvements and/or changes in this manual or in the product(s) and/or the program(s) described in this manual at any time.
Contacting Technical Support
Digi International Inc. World Headquarters
11001 Bren Road East Minnetonka, MN 55343
Phone: (866) 765-9885 toll-free U.S.A. & Canada
(801) 765-9885 Worldwide
8:00 am - 5:00 pm (U.S. Mountain Time)
Online Support: www.digi.com/support/
Email: [email protected]
Fax: 952-912-4952
ConnectCore 6 Linux BSP Reference Manual
Table of Contents
© 2014 Digi International Inc.
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ConnectCore 6 Linux BSP Reference Manual
About the ConnectCore 6 Linux BSP
This is a guide to supported devices and interfaces of the ConnectCore 6 platform in Digi
Embedded Yocto 1.6.
Linux Kernel Device Tree
Introduction
The Flattened Device Tree (FDT, or simply DT) is a data structure for describing the hardware in a system. Rather than hard coding every detail of a device into the operating system, many aspects of the hardware can be described in a data structure that is passed to the operating system at boot time. The data structure itself is a simple tree of named nodes and properties.
Nodes contain properties and child nodes. Properties are simple name-value pairs. The structure can hold any kind of data. The format is expressive and able to describe most board design aspects including:
• The number and type of CPUs
• Base addresses and size of RAM
• Busses and bridges
• Peripheral device connections
• Interrupt controllers and IRQ line connections
Advantages
• Ship one FDT image per machine (a few kB) instead of one kernel image per machine (several
MB).
• Reduce or eliminate effort needed to write machine support code (i.e. arch/arm/mach-*).
Most board specific code changes constrained to FDT file and device drivers.
• No need to allocate a new global ARM machine id for each new board variant.
• Reduce the need to recompile the kernel. One kernel image with support for different hardware can be shipped and be run in different variants (each one with its own FDT describing the hardware which is really available).
• Expressive format to describe related board variants without allocating new machine numbers or new ATAGs.
• U-Boot firmware can inspect and modify an FDT image before booting.
Formats
• *.dts: This is a Device Tree file in plain text (human readable).
• *.dtsi: This is like a DTS include file (a plain text file to be included by a DTS file).
• *.dtb: This is a Device Tree Blob: a binary representation of a Device Tree, once compiled with the Device Tree compiler.
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ConnectCore 6 Linux BSP Reference Manual
Platform Device Tree Files
The DTS file for the
ccimx6adpt
platform can be found in the kernel source code tree under: arch/arm/boot/dts/imx6-ccimx6adpt-ldo.dts
This DTS file includes other DTS and DTSI file in the same path.
Unsupported Devices
The following devices or interfaces are not supported in the BSP of the Early Availability (EA) Kit:
• ADC
• Camera
• LCD parallel interface
• Power management
• PWM (on CPU)
Bluetooth
Bluetooth (if supported by the Atheros wireless chip variant) is connected to UART2.
The MAC address of the Bluetooth interface is taken from U-Boot environment variable which is populated by U-Boot on the Device Tree before booting Linux.
btaddr
There is no generic Device Tree binding for the Bluetooth interface. Digi has created a
bluetooth entry node to pass the driver the MAC address (filled-in by U-Boot) and the power down GPIO.
bluetooth {
digi
, pwrdown
gpios = <& gpio_extender 4
0
>;
} ;
/* U‐Boot will fill in the MAC address here */
Note:
Due to a HW bug in the module, Bluetooth is not supported in version 1 of the
ConnectCore 6 module.
CAN Bus
The CPU has two Flexcan CAN ports. The CAN support is based on the SocketCAN stack. For more information about this project, documentation, and API, please refer to http:// developer.berlios.de/projects/socketcan/
.
FlexCAN Device Tree binding is described at
Documentation/devicetree/bindings/net/can/fslflexcan.txt
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ConnectCore 6 Linux BSP Reference Manual
Information about programming the CAN socket interface is given in the kernel tree under
Documentation/networking/can.txt
.
Each CAN port appears like a networking interface in the form can
The ports are disabled by default. To configure the CAN, first the bitrate must be set using tool, for example:
x
where
x
is the port number.
ip
# ip link set can0 type can bitrate 500000
To enable a port execute this command (specifying the appropriate port number):
# ifconfig can0 up
A sample application called
can_test
is available and can be added to the rootfs by adding “dey-
examples” to the EXTRA_IMAGE_FEATURES of your
local.conf
or by adding “dey-examples-
can” to IMAGE_INSTALL_append. This sample application performs several operations on the
CAN node, like sending and receiving messages. An additional CAN node is needed in the other end of the bus for the application to work (a CAN analyzer, for example).
For example, to send an 8-bit CAN message to node 'can0' with ID '0x12' and the data pattern
'0x65':
# can_test -l 1 -b 8 -d can0 -i 0x12 -p 0x65 -m
And to receive a similar message:
# can_test -l 1 -b 8 -d can0 -i 0x12 -p 0x65
For more information see the applications help with can_test --help
.
Ethernet
The ConnectCore 6 supports both Gigabit and 10/100 Ethernet. By default, the Ethernet interface is configured for Gigabit.
FEC driver Device Tree binding is described at
Documentation/devicetree/bindings/net/fsl-fec.txt
To configure Ethernet for 10/100 you need to do the following change to the Device Tree:
© 2014 Digi International Inc.
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ConnectCore 6 Linux BSP Reference Manual diff ‐‐git a/arch/arm/boot/dts/imx6‐ccimx6qdladpt.dtsi b/arch/arm/boot/dts/imx6‐ ccimx6qdladpt.dtsi index cb713e47d833..0a6adaa4e08d
100644
‐‐‐ a/arch/arm/boot/dts/imx6‐ccimx6qdladpt.dtsi
+++ b/arch/arm/boot/dts/imx6‐ccimx6qdladpt.dtsi
@@ ‐ 200,7 + 200,7 @@
};
-
/* 10/100/1000 KSZ9031 PHY */
+/*
&fec {
pinctrl‐names = "default";
pinctrl‐0 = <&pinctrl_enet_4>;
@@ ‐211,10 +211,9 @@
phy‐supply = <&ldo4>;
status = "okay";
};
-
+*/
/* 10/100 LAN8710 PHY */
‐/*
&fec {
pinctrl‐names = "default";
pinctrl‐0 = <&pinctrl_enet_5>;
@@ ‐225,7 +224,6 @@
phy‐supply = <&ldo4>;
status = "okay";
};
‐*/
&gpc {
fsl,cpu_pupscr_sw2iso = <0xf>;
Note:
Due to a HW bug on the Adapter board, 10/100 Ethernet does not work on the
Adapter.
The MAC address is taken from U-Boot environment variable
Boot on the Device Tree before booting Linux.
ethaddr
which is populated by U-
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ConnectCore 6 Linux BSP Reference Manual
The Freescale i.MX6 CPU has a documented errata ERR004512 whereby the maximum performance of Gigabit ENET is limited to 400Mbps (total for Tx and Rx).
GPIO
The CPU has seven GPIO ports, six with 32 GPIOs and one with 14 GPIOs. GPIOs are multiplexed with different functionalities of the chip. IOMUX of the pins is done at the device tree.
GPIO Device Tree binding is described at
Documentation/devicetree/bindings/gpio/fsl-imxgpio.txt
The GPIOs can be easily accessed from the sysfs. For information about how to manage the
GPIOs from sysfs, refer to the Linux kernel documentation at
Documentation/gpio.txt
.
The JSCCWMX53 development board contains two user LEDs and two user buttons that can be used to test the GPIOs.
Port pin
Linux gpio #
User LED1 User LED2
GPIO2_2 GPIO2_3
34 35
User Button 1 User Button 2
GPIO2_4 GPIO2_5
36 37
A sample application called
gpio_sysfs_test
is available and can be added to the rootfs by adding
“dey-examples” to the EXTRA_IMAGE_FEATURES of your
examples-gpio-sysfs” to IMAGE_INSTALL_append.
local.conf
or by adding “dey-
I2C
The CPU has three I2C ports. I2C2 is connected to the Dialog DA9063 PMIC and the Kinetis CPU and cannot be used for other peripherals.
I2C3 is connected to the HDMI, LCD touch screen, camera, audio codec, and routed to the
Adapter board for additional peripheral connections on the development board.
I2C Device Tree binding is described at
Documentation/devicetree/bindings/i2c/i2c-imx.txt.
One-Time Programmable (OTP) Bits
The i.MX6 CPU contains several one-time programmable bits (also known as e-fuses).
The OTP bits can be read and programmed through the sysfs, under
/sys/fsl_otp
.
WARNING:
Programming the OTP bits is an irreversible operation that could potentially brick your module. Please don’t program the OTP bits unless you are sure of what you are doing
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ConnectCore 6 Linux BSP Reference Manual
Real Time Clock (RTC)
The Dialog DA9030 PMIC provides an Real Time Clock (RTC) circuit with alarm function. To preserve the date and time during power off, the RTC must be powered externally through a battery.
DA9030 PMIC’s binding is described at
Documentation/devicetree/bindings/mfd/da9063.txt
.
For information about RTC control in Linux please refer to the kernel documentation at
Documentation/rtc.txt
.
A sample application called
rtc_test
examples” to the EXTRA_IMAGE_FEATURES of your
rtc” to IMAGE_INSTALL_append.
is available and can be added to the rootfs by adding “dey-
local.conf
or by adding “dey-examples-
SD/SDIO/MMC controller
The CPU has four uSDHC controllers:
• uSDHC1 is internally connected to the Atheros wireless chip.
• uSDHC2 is available at the module and connected in the development board to a micro SD socket.
• uSDCH3 is available at the module but also internally connected to the Atheros chip Bluetooth
UART in modules with Bluetooth support (in such modules this controller cannot be used).
• uSDHC4 is internally connected to the eMMC.
MMC binding is described at
Documentation/devicetree/bindings/mmc/mmc.txt
Serial port
The CPU has five UARTs. UART1 is a full modem whereas the other four UARTS (2..5) are only four wires.
UART2 is internally connected to the Atheros chip Bluetooth UART in modules with Bluetooth support (in such modules this UART cannot be used).
Please refer to the hardware reference manual of your board to determine available ports and multiplexed functionality.
The driver only supports RS-232 mode. UART binding is described at
Documentation/devicetree/ bindings/tty/serial/fsl-imx-uart.txt
The standard serial programming API applies to the serial ports. For information about serial programming, see the
Serial Programming HOWTO
at
http://tldp.org/HOWTO/Serial-
Programming-HOWTO/index.html
or the
Serial Programming Guide for POSIX Operating Systems
at
http://digilander.libero.it/robang/rubrica/serial.htm
.
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ConnectCore 6 Linux BSP Reference Manual
Serial Peripheral Interface (SPI)
The CPU has five SPI controllers. Please refer to the hardware reference manual of your board to determine available ports and multiplexed functionality.
ECSPI2 used to communicate with the Kinetis CPU (on module variants with Kinetis) and is routed to the development board SPI connector.
SPI binding is described at
Documentation/devicetree/bindings/spi/fsl-imx-spi.txt
A sample application called
spi_test
is available to use with spidev driver to test the port in loopback mode by connecting MISO and MOSI lines. The application can be added to the rootfs by adding “dey-examples” to the EXTRA_IMAGE_FEATURES of your
“dey-examples-spidev” to IMAGE_INSTALL_append.
local.conf
or by adding
Sound
The module can output sound through through external audio chip SGTL5000 on the development board (default) or through the HDMI interface. The available cards can be listed with:
# aplay -L null
Discard all samples (playback) or generate zero samples (capture) default:CARD=sgtl5000audio
sgtl5000-audio,
Default Audio Device sysdefault:CARD=sgtl5000audio
sgtl5000-audio,
Default Audio Device default:CARD=imxhdmisoc
imx-hdmi-soc,
Default Audio Device sysdefault:CARD=imxhdmisoc
imx-hdmi-soc,
Default Audio Device
To change the default device, please refer to ALSA documentation at http://www.alsaproject.org/main/index.php/Asoundrc
.
The sound driver can be accessed using the ALSA API. ALSA utilities package also offer user space applications:
• aplay: for playback
• arecord: for recording
• alsactl: for configuration
• amixer: for specific control setup
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ConnectCore 6 Linux BSP Reference Manual
Several predefined configuration files are stored at
/var/lib/alsa
:
• asound.inline_play.state: for recording from LINE-IN and playback
• asound.inline.state: for recording from LINE-IN only (no playback)
• asound.micro_play.state: for recording from MIC and playback
• asound.micro.state: for recording from MIC only (no playback)
• asound.play.state: for playback only
For enabling one of the above described configuration files, the application alsactl must be executed. For example, for enabling recording the input-stream over the line-in, execute:
# alsactl restore -f /var/lib/alsa/asound.inline.state
Touch screen
The ConnectCore 6 kit uses a Fusion 10” LCD display with touch screen controller. Touch screen is connected to I2C3 bus on the development board.
Although the display is multi-touch, user space does only support single touch events.
U-Boot Environment
U-Boot environment can be accessed from Linux user space using the
fw_printenv
and
fw_setenv
tools.
Config file eMMC.
/etc/fw_env.config
determines the device, start offset, and size of the environment and its redundant copy. The default config file points to the U-Boot environment stored in the
If booting from a U-Boot in external micro SD card, the U-Boot environment is stored at the micro SD card, and the config file must be changed to point to that block device instead.
USB
The CPU has four USB controllers. The default IOMUX exposes USB_OTG and USB_H1.
USB Device Tree bindings are described at
Documentation/devicetree/bindings/usb/ci13xxximx.txt
and
Documentation/devicetree/bindings/usb/mxs-phy.txt.
USB device
USB_OTG port can work as USB device.
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ConnectCore 6 Linux BSP Reference Manual
Serial gadget
To load the serial gadget:
# modprobe configfs
# modprobe libcomposite
# modprobe usb_f_acm
# modprobe u_serial
# cd
The serial gadget exposes a TTY style serial line interface, usable with
Most Linux hosts can talk to this using the generic usb-serial driver. The latest versions of this driver implement the CDC ACM class. This driver works with the MS-Windows usbser.sys driver, the Linux cdc-acm driver, and many other USB Host systems. The kernel has a detailed documentation file at
Documentation/usb/gadget_serial.txt
your target as a serial port to the eyes of a USB host.
minicom
and similar tools. with information on how to set up this driver with both Windows and Linux systems. Follow the instructions in this file for exposing
Ethernet gadget
By loading the Ethernet gadget the target enumerates to the host computer as an Ethernet device, using the usbnet driver on Linux hosts or Microsoft's RNDIS driver on Windows hosts.
To load the Ethernet gadget:
# modprobe configfs
# modprobe libcomposite
# modprobe g_ether
This command will create an Ethernet interface in the target called
MAC addresses to the target and the host.
usb0
and will assign random
We need to give this new network interface
usb0
an IP address, for example:
# ifconfig usb0 192.168.44.30 netmask 255.255.255.0
On a host computer, the usbnet module must be loaded so that the device is recognized:
$ sudo modprobe usbnet
$ ifconfig usb0 192.168.44.1 netmask 255.255.255.0
Now the target can be accessed via the USB cable as if it was an Ethernet port. You can do a ping or open a telnet session from the host to the target or viceversa.
File-backed mass storage gadget
This gadget implements the USB Mass Storage class, appearing to the host as a SCSI disk drive.
A file or block device can be used as a backing store for the drive.
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ConnectCore 6 Linux BSP Reference Manual
To load the file-backed storage gadget:
# modprobe configfs
# modprobe libcomposite
# modprobe g_mass_storage file=<filename>
For more information please read the kernel documentation at
Documentation/usb/massstorage.txt.
USB Host
USB_H1 port works as USB host. USB_OTG can work as USB host as well.
Video
Video can be output through the HDMI interface or two LVDS ports.
Device Tree bindings for IPU, framebuffer and LCD display are described at
Documentation/ devicetree/bindings/fb/fsl_ipuv3_fb.txt.
U-Boot boot loader contains three variables from which it builds the video kernel command line parameters:
• video0: set by default to LVDS with Fusion 10” LCD:
dev=ldb,LDB-HSD101PFW2,bpp=32
• video1: set by default to HDMI:
dev=hdmi,1920x1080M@60,bpp=32
• video2: set by default to OFF:
off
The kernel command line expands these variables like this: video=mxcfb0:${video0} video=mxcfb1:${video1} video=mxcfb2:${video2}
The possible combinations are:
• Only HDMI
• Set video0 to
dev=hdmi,1920x1080M@60,bpp=32
• Set video1 and video2 to
off
• Only LVDS with Fusion 10” LCD display:
• Set video0 to
dev=ldb,LDB-HSD101PFW2,bpp=32
• Set video1 and video2 to
off
• LVDS and HDMI:
• Set video0 to
dev=ldb,LDB-HSD101PFW2,bpp=32
• Set video1 to
dev=hdmi,1920x1080M@60,bpp=32
• Set video2 to
off
There are two LVDS interfaces, one routed to the Development board (LVDS0) and another routed to the Adapter board (LVDS1).
By default, the LVDS output is driven to LVDS0 (connector on the development board). To drive the output to LVDS1 (connector on the Adapter board) you need to do the following change to the Device Tree:
© 2014 Digi International Inc.
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ConnectCore 6 Linux BSP Reference Manual diff -git a / arch / arm / boot / dts / imx6 ccimx6adpt .
dts b / arch / arm / boot / dts / imx6 ccimx6adpt .
dts index b00644bdd7a9
..
25e9d5b49846 100644
---
a / arch / arm / boot / dts / imx6
ccimx6adpt
.
dts
+++ b / arch / arm / boot / dts / imx6
ccimx6adpt
.
dts
@@ 243 , 10 + 243 , 10 @@
&ldb {
ipu_id = <0>;
‐ disp_id = <0>;
+ disp_id = <1>;
ext_ref = <1>;
‐ mode = "sin0";
+ mode = "sin1";
sec_ipu_id = <0>;
‐ sec_disp_id = <1>;
+ sec_disp_id = <0>;
status = "okay";
};
Backlight
The Dialog DA9030 PMIC provides three PWM outputs two of which are used for LCD backlight control.
DA9030 PMIC’s gpio binding is described at
Documentation/devicetree/bindings/gpio/gpioda9063.txt
For information about backlight control in Linux please refer to the kernel documentation at
Documentation/ABI/stable/sysfs-class-backlight
.
Watchdog
Device Tree binding for watchdog is described at
Documentation/devicetree/bindings/watchdog/ fsl-imx-wdt.txt.
A sample application called
wd_test
is available and can be added to the rootfs by adding “dey-
examples” to the EXTRA_IMAGE_FEATURES of your
watchdog” to IMAGE_INSTALL_append.
local.conf
or by adding “dey-examples-
The watchdog test application sets the watchdog timeout value and refreshes the watchdog timer every second during the test time. After the test time is over, the watchdog is not refreshed anymore and the driver executes a reset.
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ConnectCore 6 Linux BSP Reference Manual
For further information about the watchdog interface refer to the Linux kernel documentation at
Documentation/watchdog/
.
Wireless
The module assembles an Atheros wireless chip connected to uSDHC1.
The MAC address is taken from U-Boot environment variable
Boot on the Device Tree before booting Linux.
wlanaddr
which is populated by U-
There is no generic Device Tree binding for the Bluetooth interface. Digi has created a wireless entry node to pass the driver the MAC address (filled-in by U-Boot) and the power down GPIO:
wireless {
digi
, pwrdown
gpios = <& gpio_extender 3
0
>;
} ;
/* U‐Boot will fill in the MAC address here */
© 2014 Digi International Inc.
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Key Features
- Supported devices and interfaces
- Device tree files
- Detailed information on configuration and usage
- Digi Embedded Yocto 1.6 platform