View source for MCM-iMX8M-Plus: Yocto Linux: How-To Guide

=Device Tree=
== Available Device Tree ==
The current release come with these dtb files:
{| class="wikitable" style="text-align:left;"
|-
| align="center" | '''DTB''' 
| align="center" | '''Hardware Configuration and Features'''
| align="center" | '''Required Jumpers Settings'''
|-
| align="" |mcm-imx8m-plus-som.dtb
| align="" |minimal module configuration
|-
| align="" |mcm-imx8m-plus-headless.dtb
| align="" |minimal module configuration<br> + can + pcie + eb-eth + sd8997 + mmc2
| align="" |
|-
| align="" |mcm-imx8m-plus.dtb
| align="" |default EVK hardware configuration: headless + mipi dsi + lvds + hdmi
| align="" |
|-
| align="" |mcm-imx8m-plus-evk-eth.dtb
| align="" |default EVK hardware configuration: headless + mipi dsi + lvds + hdmi + P5:eb-eth 
| align="" |
|-
| align="" |mcm-imx8m-plus-evk-audio.dtb
| align="" |default EVK hardware configuration: headless + mipi dsi + lvds + hdmi + P5:eb-audmx9 
|-
| align="" |mcm-imx8m-plus_mipi-csi1-ar1335-af.dtb
| align="" |default hardware configuration + mipi csi1 enabled + ar1335_af sensor on the Ppp;
| align="" |Eee is on
|-
| align="" |mcm-imx8m-plus_mipi-csi2-ar1335-af.dtb
| align="" |default hardware configuration + mipi csi2 enabled + ar1335_af sensor on the Ppp;
| align="" |Eee is off
|-
| align="" |mcm-imx8m-plus-usbdev.dtb
| align="" |default hardware configuration + USB1 as a peripheral;
| align="" |Jjj is in use
|-
| align="" |mcm-imx8m-plus-hdmi.dtb
| align="" |default hardware configuration  w/out lvds and mipi dsi; hdmi display only;
| align="" |Ppp is in use
|-
| align="" |mcm-imx8m-plus-lvds.dtb
| align="" |default hardware configuration w/out hdmi and mipi dsi; lvds display only;
| align="" |Ppp/pp lvds iface/touch is in use
|-
| align="" |mcm-imx8m-plus-mipi.dtb
| align="" |default hardware configuration w/out hdmi and lvds; mipi dsi display only;
| align="" |Ppp/Ppp mipi iface/touch is in use
|-
| align="" |mcm-imx8m-plus-ldo4.dtb
| align="" |default hardware configuration + ldo4 bypass settings from U-Boot;
| align="" |
|-
| align="" |mcm-imx8m-plus_mipi-csi1-ar1335-mcu.dtb
| align="" |default hardware configuration + mipi csi1 enabled + ar1335 sensor on the Ppp;
| align="" |Eee is off
|-
| align="" |mcm-imx8m-plus_mipi-csi2-ar1335-mcu.dtb
| align="" |default hardware configuration + mipi csi2 enabled + ar1335 sensor on the Ppp;
| align="" |Eee is off
|-
|}

== Available Device Tree Overlays ==
{{Note|The overlay load mode available with '''run bsp_bootcmd''' mode only.}}
{| class="wikitable" style="text-align:left;"
|-
| align="center" | '''DTB Overlay''' 
| align="center" | '''Hardware Configuration and Features'''
| align="center" | '''Required Jumpers Settings'''
|-
| align="" |mcm-imx8m-plus-mmc2.dtbo
| align="" |enable SD-card on mmc2;
| align="" |
|-
| align="" |mcm-imx8m-plus-sd8997.dtbo
| align="" |enable wifi/bt sd8997 on mmc1;
| align="" |
|-
| align="" |mcm-imx8m-plus-mipi.dtbo
| align="" |enable mipi dsi display;
| align="" |
|-
| align="" |mcm-imx8m-plus-lvds.dtbo
| align="" |enable lvds display;
| align="" |
|-
| align="" |mcm-imx8m-plus-hdmi.dtbo
| align="" |enable hdmi display;
| align="" |
|-
| align="" |mcm-imx8m-plus-usbdev.dtbo
| align="" |enable USB1 as a peripheral;
| align="" |
|-
| align="" |mcm-imx8m-plus-rpmsg.dtbo
| align="" |enable rpmgs on for M7;
| align="" |
|-
| align="" |mcm-imx8m-plus_mipi-csi1-ar1335-af.dtbo
| align="" |enable mipi csi1 ar1335-af sensor on the P48;
| align="" |E18 is on
|-
| align="" |mcm-imx8m-plus_mipi-csi2-ar1335-af.dtbo
| align="" |enable mipi csi2 ar1335-af sensor on the P50;
| align="" |E16 is on
|-
| align="" |mcm-imx8m-plus_mipi-csi1-ar1335-mcu.dtbo
| align="" |enable mipi csi1 ar1335 sensor on the P49;
| align="" |E18 is off
|-
| align="" |mcm-imx8m-plus_mipi-csi2-ar1335-mcu.dtbo
| align="" |enable mipi csi2 ar1335 sensor on the P51;
| align="" |E16 is off
|-
| align="" |mcm-imx8m-plus-eb-audimx9.dtbo
| align="" |enable wm8962-audio codec on P15;
| align="" |
|-
| align="" |mcm-imx8m-plus-eb-eth.dtbo
| align="" |enable FEC network interface on P15;
| align="" |
|-
| align="" |mcm-imx8m-plus-uart1.dtbo
| align="" |enable uart1 on P13[1-TXD,3-RXD] as RS232;
| align="" |
|-
| align="" |mcm-imx8m-plus-uart3.dtbo
| align="" |enable uart3 on P13[2-TXD,4-RXD] as RS232;
| align="" |J22 - RS485
|-
| align="" |mcm-imx8m-plus-uart4.dtbo
| align="" |enable uart1 on P13[8-TXD,10-RXD] as RS232;
| align="" |P17 - RS232
|-
|}

==Set a device tree==
The current release provides two methods to switch between dtb files:
* U-Boot environment
The U-boot '''fdtfile''' variable contains the device tree name that will be loaded into the RAM.
This variable can be changed by:
{| class="wikitable" style="text-align:left;"
|-
| align="" | '''Environment''' 
| align="" | '''Command''' 
|-
| align="" |U-Boot
| align="" |setenv fdtfile <fdt_file_name>; saveenv;
|-
| align="" |Linux
| align="" |fw_setenv fdtfile <fdt_file_name>
|-
|}
* GRUB environment (if the image was created with the meta-compulab-uefi layer)
{| class="wikitable" style="text-align:left;"
|-
| align="" | '''Environment''' 
| align="" | '''Command/Procedure''' 
|-
| align="" |GRUB Boot Menu
| align="" |Goto "Advanced Boot Options" and choose a device tree from the provided dtb list.
|-
| align="" |Linux
| align="" |grub-editenv /boot/EFI/BOOT/grubenv set fdt_file=<fdt_file_name>
|-
|}

= U-Boot =
== Basic commands ==
* Restore default boot environment:
<pre>
env default -a
</pre>
* List boot candidates:
<pre>
printenv bootlist
</pre>
* Get/Set device tree:
{| class="wikitable" width="40%" style="text-align:left;"
|-
| align="" | '''get''' 
| align="" | '''set'''
|-
| align="" |printenv fdtfile
| align="" |setenv fdtfile mcm-imx8m-plus-headless.dtb
|-
|}
* Get/Set device tree overlay:
The lates U-Boot supports device tree file overlays to be loaded after the main file.<br>The '''fdtofile''' can be a list of device tree files.
{{Note| The boot process will fail if a file in the fdtofile is not found on the boot device. }}
{| class="wikitable" width="40%" style="text-align:left;"
|-
| align="" | '''get''' 
| align="" | '''set'''
|-
| align="" |printenv fdtofile
| align="" |setenv fdtofile "mcm-imx8m-plus-mipi.dtbo mcm-imx8m-plus_mipi-csi1-ar1335-af.dtbo"
|-
|}
== LDO4 - secondary RGMII voltage control ==
PMIC LDO4 controls voltage rail that powers secondary RGMII signal group.</br>
By default LDO4 is configured for 1.8V operation.<br>In order to control LDO4 settings and have them passed correctly to the Linux kernel, use the command and device tree described below.
* ldo4 command:
<pre>
help ldo4
</pre>
* ldo4 modes:
{| class="wikitable" width="40%" style="text-align:left;"
|-
| width="20%" align="" | '''mode                       ''' 
| align="" | '''commands                   '''
|-
| align="" |1v8 mode
| align="" |ldo4 18; boot
|-
| align="" |3v3 mode
| align="" |ldo4 33; boot
|-
| align="" |off mode
| align="" |ldo4 0;boot
|-
|}

* The device tree overlay to use.<br>This device tree removes the LDO4 regulator from the Linux kernel control.<br>
<pre>
setenv fdtoflie mcm-imx8m-plus-ldo4.dtbo
setenv bootcmd 'run bsp_bootcmd'; saveenv
</pre>
* Limit the max regulator value<br>In order to continue using this LDO4 in Linux, but with respect to the U-Boot ldo4 settings, modify the ldo4 node.<br>The sample below limits the upper ldo4 value to 1v8.
<pre>
ldo4: LDO4 {
	regulator-name = "LDO4";
	regulator-min-microvolt = <800000>;
	regulator-max-microvolt = <1800000>;
	regulator-boot-on;
	regulator-always-on;
};
</pre>

== Overlay load mode example ==
CompuLab U-Boot has an option to apply a device tree overlay after loading the main device tree file.<br>
In order to use this option, the fdtofile U-Boot environment variable must be set.<br>
The fdtofile can be a list of dtbo files.

{| class="wikitable" width="40%" style="text-align:left;"
|-
| align="" | '''U-Boot command''' 
| align="" | '''description'''
|-
| align="" |setenv fdtfile mcm-imx8m-plus-headless.dtb
| align="" |set the main device tree w/out any display interface enabled
|-
| align="" |setenv fdtofile 'mcm-imx8m-plus_mipi-csi1-ar1335-af.dtbo mcm-imx8m-plus-lvds.dtbo mcm-imx8m-plus-eb-audimx9.dtbo'
| align="" |set the overlay list that enables:<br>lvds display<br>ar1335-af sensor on the mipi csi1<br>wm8962 codec 
|-
| align="" |setenv bootcmd 'run bsp_bootcmd'
| align="" |set the boot command that allows loading the device tree overlays
|-
| align="" |saveenv
| align="" |save the environment
|}

<pre>
setenv fdtfile mcm-imx8m-plus-headless.dtb
setenv fdtofile 'mcm-imx8m-plus_mipi-csi1-ar1335-af.dtbo mcm-imx8m-plus-lvds.dtbo mcm-imx8m-plus-eb-audimx9.dtbo'
saveenv
</pre>

{{Note| Overlay load mode works with '''run bsp_bootcmd''' only. }}

= Boot Modes =
The current release provides two methods to boot up the system:
{| class="wikitable" style="text-align:left;"
|-
| align="" | ''' ... ''' 
| align="" | '''Embedded w/out GRUB'''
| align="" | '''Desktop with GRUB'''
|-
| align="" |U-Boot bootcmd
| align="" |run bsp_booctmd
| align="" |run distro_bootcmd
|-
| align="" |Boot Menu
| align="" |n/a
| align="" |'''GNU GRUB  version 2.06'''<br>*Boot Linux Image-6.1.55-3.0+g8c44f7d3805c<br> Install NXP i.MX Release Distro 6.1-mickledore (mickledore)<br> Advanced Boot Options<br>
|-
| align="" |pros/cons
| align="" |'''pros''':<br>Fast boot<br>Allows loading device tree overlays<br>'''cons''':<br>Install Mode requires to Linux boot 1-st<br> 
| align="" |'''pros''':<br>Install Mode<br>Allows changing the device tree for the current session<br>'''cons''':<br>Increases the boot time by the GRUB timeout<br> 
|-
|}


= Serial Console =
MCM-iMX8M-Plus provides serial console on UART2.</br>
SB-MCMIMX8Plus evaluation carrier-board exposes the console UART via CP2104 serial-to-USB bridge on connector [[MCM-iMX8M-Plus: Evaluation Kit: Hardware Guide#Connector_Locations | '''P13''']].
== Connecting to a host PC ==
# Use a micro-USB cable to connect the console connector '''P13''' to a USB port on your host PC.
# Make sure the CP2104 driver is available with your operating system, otherwise install CP2104 driver onto the host PC from https://www.silabs.com/documents/public/software/CP210x_Windows_Drivers_with_Serial_Enumeration.zip
# Identify the host PC interface and port number that will be used for communication with the MCM-iMX8M-Plus evaluation kit:
#* In most Linux PCs, the serial port will be denoted as one of the following (where n is a positive integer): /dev/ttyUSB0, /dev/ttyUSB1 ... /dev/ttyUSBn
#* In Windows PCs, the serial port usually will be denoted as one of the following (where n is a positive integer): COM1, COM2 ... COMn
# Start a terminal emulation program (such as [https://www.putty.org/ PuTTY] on Windows or minicom on Linux).
# In the port configuration section of the terminal emulation program select the port identified in previous step and set the following serial port parameters:
<blockquote>
{{:SB-SOM: serial port parameters table}}
</blockquote>

=Display=
MCM-iMX8M-Plus evaluation kit supports three types of display interfaces: MIPI-DSI, LVDS and HDMI.</br>
All interfaces are enabled in the default '''mcm-imx8m-plus.dtb''' device tree file.

==MIPI-DSI==
The MCM-iMX8M-Plus evaluation kit includes the Startec KD050HDFIA 5" MIPI-DSI LCD panel. 

Connect the MIPI-DSI display to connectors [[MCM-iMX8M-Plus: Evaluation Kit: Hardware Guide#Connector_Locations | '''P22''' and '''P45''']] on the SB-MCMIMX8Plus carrier-board.

The Linux device node for the MIPI-DSI display:
 /sys/class/drm/card0/card0-DSI-1/
This device node contains information about the display, such as its supported modes and its current configuration.

==LVDS==
SB-MCMIMX8Plus supports direct connection with the Startec KD070HDTLA020 7" LVDS LCD panel.</br>
Connect the display data cable to connector [[MCM-iMX8M-Plus: Evaluation Kit: Hardware Guide#Connector_Locations | '''P11''']].
Connect the display touch-panel cable to connector [[MCM-iMX8M-Plus: Evaluation Kit: Hardware Guide: Hardware Guide#Connector_Locations | '''P5''']].

==HDMI==

SB-MCMIMX8Plus supports HDMI output on connector [[MCM-iMX8M-Plus: Evaluation Kit: Hardware Guide#Connector_Locations | '''P14''']]. Connect to standard monitor using an HDMI cable.

==Display Manager==
MCM-iMX8M-Plus Yocto uses Weston as the default display manager. It can be configured in ''/etc/xdg/weston/weston.ini''.</br>
For example the transform setting can be set to rotate-90, rotate-180, rotate-270, or commented out.</br>
In order to apply the configuration, you need to restart the weston display manager:
 systemctl stop weston
 systemctl start weston

=USB=
i.MX8M Plus SoC is equipped with two dual-role USB3.0 controllers and PHYs.<br>
USB1 can be configured as host or device, while the USB2 is configured permanently for host mode.

=== USB1 mode switch ===
The SOM is able to work as a host or as a device. Due to a HW limitation the mode switch does not work automatically yet.
* host<br>The device works in a host mode unless the '''mcm-imx8m-plus-usbdev.dtbo''' is applied.
* device<br>The device works in a device mode when the '''mcm-imx8m-plus-usbdev.dtbo''' is applied.<br>
==== Enable device mode ====
<pre>
setenv fdtofile 'mcm-imx8m-plus-usbdev.dtbo'
setenv bootcmd 'run bsp_bootcmd'
saveenv
</pre>

==== USB device/gadget mode to use in Linux ====
{| class="wikitable" style="text-align:left;"
|-
| align="" | '''USB device mode''' 
| align="" | '''Command/Procedure''' 
| align="" | '''Test scenario''' 
|-
| align="" |usb serial device
| align="" |modprobe g_serial
| align="" |<pre>device: systemctl start serial-getty@ttyGS0
Linux PC: sudo minicom -D /dev/ttyACM0 115200</pre>
|-
| align="" |usb network device
| align="" |modprobe g_ether
| |
|-
| align="" |usb mass storage device
| align="" |modprobe g_mass_storage file=/dev/sdX
| |
|-
|}

= SPI bus =
MCM-iMX8M-PLUS features three Enhanced Configurable Serial Peripheral Interface (eCSPI) modules.<br>
The CompuLab EVK uses the ECSPI2 bus in order to show the usage of the Linux spidev interface.

== spidev ==
* Device tree to use:
<pre>
setenv fdtofile 'mcm-imx8m-plus-spidev.dtbo'
setenv bootcmd 'run bsp_bootcmd'
saveenv
</pre>

* Device Tree:
<pre>
&iomuxc {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_hog>;
	....
	pinctrl_ecspi2: ecspi2grp {
		fsl,pins = <
			MX8MP_IOMUXC_ECSPI2_SCLK__ECSPI2_SCLK		0x82
			MX8MP_IOMUXC_ECSPI2_MOSI__ECSPI2_MOSI		0x82
			MX8MP_IOMUXC_ECSPI2_MISO__ECSPI2_MISO		0x82
		>;
	};

	pinctrl_ecspi2_cs: ecspi2cs {
		fsl,pins = <
			MX8MP_IOMUXC_ECSPI2_SS0__GPIO5_IO13		0x40000
		>;
	};
	....
};

&ecspi2 {
	#address-cells = <1>;
	#size-cells = <0>;
	fsl,spi-num-chipselects = <1>;
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_ecspi2 &pinctrl_ecspi2_cs>;
	cs-gpios = <&gpio5 13 GPIO_ACTIVE_LOW>;
	status = "okay";

	spidev1: spi@0 {
		reg = <0>;
		compatible = "rohm,dh2228fv";
		spi-max-frequency = <500000>;
	};
};
</pre>

* System board setup:<br>Short Pxx.yy(MOSI) and  Pxx.yy(MISO) pins.

* Linux command line test:
<pre>
root@mcm-imx8m-plus:~# spidev_test -p 1234/5678 -v -D /dev/spidev1.0
spi mode: 0x4
bits per word: 8
max speed: 500000 Hz (500 kHz)
TX | 31 32 33 34 2F 35 36 37 38 __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __  |1234/5678|
RX | 31 32 33 34 2F 35 36 37 38 __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __  |1234/5678|
</pre>

= WiFi =
SB-MCMIMX8Plus features an optional 802.11ax WiFi interface, implemented with the Intel WiFi 6 AX210 module.<br>
The [https://manpages.debian.org/stretch/network-manager/nmcli.1.en.html NetworkManager] can be used to manage WiFi interface.

== Enable/Disable WiFi Interface ==
* To enable WiFi interface:
:<pre>nmcli radio wifi on</pre>
* To disable WiFi interface:
:<pre>nmcli radio wifi off</pre>

== Network Scanning ==
* Sample WiFi scanning:
:<pre>nmcli dev wifi list</pre>
:The output will show the list of Access Points and Ad-Hoc cells in range.

== Connecting to Access Point ==
In the following example:
* Replace <SSID> and <PASSWORD> with the actual access point parameters:
:<pre>nmcli device wifi connect <SSID> password <PASSWORD> name WifiCon</pre>
* Disconnect wireless network:
:<pre>nmcli connection down WifiCon</pre>
* Connect wireless network again:
:<pre>nmcli connection up WifiCon</pre>

== Creating Access Point ==
{{Note|Debian 12<br>ipv4 forwarding must be turned on manually}}
* Enable port forwarding:
:<pre>sed -i 's/^#\(net.ipv[4,6].*forward\)/\1/' /etc/sysctl.conf</pre>
In the following example:
* Replace <SSID> and <PASSWORD> with desired access point parameters:
:<pre>nmcli device wifi hotspot ssid <SSID> password <PASSWORD> con-name HotspotCon</pre>
* Disable wireless AP:
:<pre>nmcli connection down HotspotCon</pre>
* Enable wireless AP again:
:<pre>nmcli connection up HotspotCon</pre>

=CAN bus=
MCM-iMX8M-PLUS features two Flexible Controller Area Network (FLEXCAN) modules.
The FlexCAN module is a full implementation of the CAN protocol specification, the
CAN with Flexible Data rate (CAN FD) protocol, and the CAN 2.0 version B protocol,
which supports both standard and extended message frames and long payloads up to 64
bytes, transferred at faster rates (up to 8 Mb/s).

==CAN interface configuration==
It is recommended configure the CAN interface, with the {{filename|iproute2}} utilities.

* To make sure the right '''ip''' utility is used, run:
<pre>
ip -V
ip utility, iproute2-v5.7.0-77-gb687d1067169 
</pre>
* Configure both CAN interface bit-rate to 1 Mbit/sec:
<pre>
ip link set can0 type can bitrate 1000000
ip link set can1 type can bitrate 1000000
</pre>
* Enable the CAN interface:
<pre>
ip link set can0 up
ip link set can1 up
</pre>

==Send/Receive packets==
Use {{filename|cansend}} and {{filename|candump}} utilities to send and receive packets via CAN interface.

* Send standard CAN frame (on the first device):
<pre>
cansend can0 111#1122334455667788
</pre>

* Send extended CAN frame (on the first device):
<pre>
cansend can0 11111111#1122334455667788
</pre>

* CAN frames (extended mode) generator, random payload, interval between two successive flames 50 msec:
<pre>
cangen -g 50 -e -D r -v can0

can: raw protocol (rev 20170425)
...
  can0  03FF0983#D7.61.FF.03.C1.F7.C1.34
  can0  19C34D32#F7.5A.C2.73.AD.0E.3F.0B
  can0  0675E391#2B.2D.D3.49
  can0  13091C55#99.32.EC.77.27.81.49.0B
  can0  098D67CF#22.50.AB.48.AD.7F.F4.26
  can0  05263FEC#1B.4C.02.45.6E
  can0  12B30E20#
  can0  1F193DF9#C5
  can0  1EB0B18F#3E.3F.DA.57.C2.FE.73.58
  can0  1E5C64D9#6F.0D.B3.63.6A
  can0  1E1DE3F9#96.48.AC.79.4E.00.27.71
  can0  0E1A11B7#75.81.70.7C.86.79.A7.77
  can0  05F8FD8B#33.F9.9B.1E.77.3D.1F
  can0  1E155FCD#E6.BA.F8.58.ED.6D.C8.10
  can0  1D91DF9E#5D.29.82.7B.97.1D.AB.5C
  can0  11FB3CDA#14.65.C3
  can0  091352C0#2C.ED
...
</pre>

* Dump all received data frames as well as error frames (on the second device):
<pre>
candump any,0:0,#FFFFFFFF

  can0  111   [8]  11 22 33 44 55 66 77 88
  can0  11111111   [8]  11 22 33 44 55 66 77 88
...
  can0  03FF0983   [8]  D7 61 FF 03 C1 F7 C1 34
  can0  19C34D32   [8]  F7 5A C2 73 AD 0E 3F 0B
  can0  0675E391   [4]  2B 2D D3 49
  can0  13091C55   [8]  99 32 EC 77 27 81 49 0B
  can0  098D67CF   [8]  22 50 AB 48 AD 7F F4 26
  can0  05263FEC   [5]  1B 4C 02 45 6E
  can0  12B30E20   [0] 
  can0  1F193DF9   [1]  C5
  can0  1EB0B18F   [8]  3E 3F DA 57 C2 FE 73 58
  can0  1E5C64D9   [5]  6F 0D B3 63 6A
  can0  1E1DE3F9   [8]  96 48 AC 79 4E 00 27 71
  can0  0E1A11B7   [8]  75 81 70 7C 86 79 A7 77
  can0  05F8FD8B   [7]  33 F9 9B 1E 77 3D 1F
  can0  1E155FCD   [8]  E6 BA F8 58 ED 6D C8 10
  can0  1D91DF9E   [8]  5D 29 82 7B 97 1D AB 5C
  can0  11FB3CDA   [3]  14 65 C3
  can0  091352C0   [2]  2C ED
...
</pre>

=Gstreamer=
Yocto Linux uses Gstreamer as a default multimedia framework. Here are some useful Gstreamer features:

Execute the following command to check all the source options:
 gst-inspect-1.0 | grep source

Execute the following command to check all the sink options:
 gst-inspect-1.0 | grep sink

==Video Playback==
{{note|The operation below requires '''root''' access.}}

MCM-iMX8M-Plus features 1080p60 H.264, VP8 video decoding capabilities. Before starting video playback, please, ensure that the display is connected to the board.

The following commands can be used to start video playback ('''1.mov''' is a media file):
* gst-play
<pre>
gst-play /path/to/1.mov
</pre>

* gplay-1.0
<pre>
gplay-1.0 /path/to/1.mov
</pre>

* gst-launch
This method is for advanced users. Please study this document before the start: [https://raw.githubusercontent.com/compulab-yokneam/Documentation/master/pdfs/i.MX8GStreamerUserGuide.pdf i.MX8GStreamerUserGuide.pdf]
<pre>
gst-launch-1.0 -v filesrc location=/path/to/1.mov ! qtdemux name=d.video_0 ! h264parse ! avdec_h264 ! autovideosink
</pre>

==Video Capturing==
{{note|The operation below requires '''root''' access.}}

=== ISI Sensors ===
* hw: an ar1335 sensor is connected to either P47 (MIPI_CSI2) or P48+E18 (MIPI_CSI1) port
* sw: a correct device tree is in use:
{| class="wikitable" style="text-align:left;"
|-
| align="" | '''Interface''' 
| align="" | '''Device tree''' 
| align="" | '''Device tree + overlay example''' 
|-
| align="" |MIPI_CSI1
| align="" |mcm-imx8m-plus_mipi-csi1-ar1335-af.dtb
| align="" |fw_setenv fdtfile mcm-imx8m-plus.dtb<br>fw_setenv fdtofile mcm-imx8m-plus_mipi-csi1-ar1335-af.dtbo<br>fw_setenv bootcmd "run bsp_bootcmd"
|-
| align="" |MIPI_CSI2
| align="" |mcm-imx8m-plus_mipi-csi2-ar1335-af.dtb
| align="" |fw_setenv fdtfile mcm-imx8m-plus.dtb<br>fw_setenv fdtofile mcm-imx8m-plus_mipi-csi2-ar1335-af.dtbo<br>fw_setenv bootcmd "run bsp_bootcmd"
|-
|}
* sw: the '''mxc-isi-cap''' is registered:
<pre>
v4l2-ctl --list-devices

 ():
        /dev/v4l-subdev0

mxc-isi-cap (platform:32e00000.isi:cap_devic):
        /dev/video0

FSL Capture Media Device (platform:mxc-md):
        /dev/media0
</pre>

=== ISP Sensors ===
* hw: an imx219 sensor is connected to P48-E18 (MIPI_CSI1) port
* sw: a correct device tree is in use:
{| class="wikitable" style="text-align:left;"
|-
| align="" | '''Interface''' 
| align="" | '''Device tree''' 
| align="" | '''Device tree + overlay example''' 
|-
| align="" |MIPI_CSI1
| align="" |mcm-imx8m-plus_mipi-csi1-imx219.dtb
| align="" |fw_setenv fdtfile mcm-imx8m-plus.dtb<br>fw_setenv fdtofile mcm-imx8m-plus_mipi-csi1-imx219.dtbo<br>fw_setenv bootcmd "run bsp_bootcmd"
|-
|}
* sw: the '''mxc-isi-cap''' is registered:
<pre>
v4l2-ctl --list-devices
 ():
        /dev/v4l-subdev0
        /dev/v4l-subdev2
        /dev/v4l-subdev3

 (csi0):
        /dev/v4l-subdev1

FSL Capture Media Device (platform:32c00000.bus:camera):
        /dev/media0

VIV (platform:viv0):
        /dev/video2

vsi_v4l2dec (platform:vsi_v4l2dec):
        /dev/video1

vsi_v4l2enc (platform:vsi_v4l2enc):
        /dev/video0

viv_media (platform:vvcam-video.0):
        /dev/media1
</pre>


For hardware setup and camera connection instructions please refer to MCM-iMX8M-Plus Hardware Guide.

===Examples===
The following commands should be used to start video capturing:

* filesink
Write stream to a file. In this example the encoded output gets saved in the '''1.mov''' media file.
<pre>
gst-launch-1.0 v4l2src device=/dev/video0 ! 'video/x-raw,width=1280,height=720,format=NV12' ! vpuenc_h264 ! filesink location=/path/to/1.mov
</pre>

* waylandsink
Output to wayland surface.
<pre>
gst-launch-1.0 v4l2src device=/dev/video0 ! 'video/x-raw,width=1280,height=720,format=NV12' ! waylandsink window-width=1280 window-height=720
</pre>
* autovideosink
Wrapper video sink for automatically detected video sink.
<pre>
gst-launch-1.0 v4l2src device=/dev/video0 ! 'video/x-raw,width=1280,height=720,format=NV12' ! autovideosink
</pre>

* Single Image Capturing
<pre>
gst-launch v4l2src num-buffers=1 ! jpegenc ! filesink location=single_buffer.jpg
</pre>

==Video streaming==
{{note|The operation below requires '''root''' access.}}
The following command should be executed on MCM-iMX8M-Plus to start video streaming:
 gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-raw, width=640, height=480 ! jpegenc ! udpsink host='''127.0.0.1''' port='''1234'''
'''127.0.0.1''' is the IP address of the host PC, and '''1234''' is the host PC port.

The following command should be executed on host PC (Linux) to receive the video stream:
 gst-launch-1.0 udpsrc port='''1234''' ! jpegdec ! autovideosink
'''1234''' is the host PC port.

=Analog Audio=
===List of available sound cards===
* aplay
<pre>
aplay -l

**** List of PLAYBACK Hardware Devices ****
card 0: audiohdmi [audio-hdmi], device 0: i.MX HDMI i2s-hifi-0 [i.MX HDMI i2s-hifi-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: wm8962audio [wm8962-audio], device 0: HiFi wm8962-0 [HiFi wm8962-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

cat /proc/asound/cards
 0 [audiohdmi      ]: audio-hdmi - audio-hdmi
                      audio-hdmi
 1 [wm8962audio    ]: wm8962-audio - wm8962-audio
                      wm8962-audio
</pre>

===Switch between the available output===
* cl-oselect allows select an output device:
<pre>
cl-oselect

1) alsa_output.platform-sound-hdmi.stereo-fallback
2) alsa_output.platform-sound-xcvr.iec958-stereo
3) alsa_output.platform-sound.analog-stereo
4) <<
Sound sink [ alsa_output.platform-sound.analog-stereo ] > 3
</pre>

===Audio playback===
* gplay-1.0 allows playing back media files:
<pre>
gplay-1.0 /path/to/media.file
</pre>


=Suspend / Resume=
{{note|The operation below requires '''root''' access.}}

MCM-iMX8M-Plus features suspend mode, which allows to minimize power consumption. 

The following command should be used to enter suspend mode:
<pre>
echo mem >/sys/power/state
</pre>

To resume normal operation press shortly the '''Power On''' button '''SW5'''.

=CPU frequency=
{{note|The operation below requires '''root''' access.}}
==CPU frequency current settings==
Execute the following command to get the current settings:
<pre>
grep -ir . /sys/devices/system/cpu/cpufreq/policy0/ 2>/dev/null

/sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq:1200000
/sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors:conservative ondemand userspace powersave performance schedutil 
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq:1200000
/sys/devices/system/cpu/cpufreq/policy0/scaling_governor:ondemand
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_max_freq:1600000
/sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies:1200000 1600000 
/sys/devices/system/cpu/cpufreq/policy0/related_cpus:0 1 2 3
/sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq:1200000
/sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed:<unsupported>
/sys/devices/system/cpu/cpufreq/policy0/stats/trans_table:   From  :    To
/sys/devices/system/cpu/cpufreq/policy0/stats/trans_table:         :   1200000   1600000 
/sys/devices/system/cpu/cpufreq/policy0/stats/trans_table:  1200000:         0        65 
/sys/devices/system/cpu/cpufreq/policy0/stats/trans_table:  1600000:        65         0 
/sys/devices/system/cpu/cpufreq/policy0/stats/total_trans:130
/sys/devices/system/cpu/cpufreq/policy0/stats/time_in_state:1200000 643
/sys/devices/system/cpu/cpufreq/policy0/stats/time_in_state:1600000 474
/sys/devices/system/cpu/cpufreq/policy0/affected_cpus:0 1 2 3
/sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq:1600000
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_transition_latency:182000
/sys/devices/system/cpu/cpufreq/policy0/scaling_driver:cpufreq-dt
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_min_freq:1200000
</pre>

==Changing the scaling governor==
Execute the following command to change the scaling governor:
<pre>
echo performance > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
</pre>

Where '''perfomance''' is name of the scaling governor.

Execute the following command to see available scaling governors:
<pre>
cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors
</pre>

Execute the following command to see current scaling governor:
<pre>
cat /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
</pre>

==Changing CPU frequency==
{{note|CPU frequency can be changed only when the scaling governoris set to '''userspace'''.}}
Execute the following command to set CPU frequency:
<pre>
echo 1200000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed
</pre>

'''1200000''' is one of the available CPU frequencies.

Execute the following command to see available CPU frequencies:
<pre>
cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies
</pre>

Execute the following command to see current CPU frequency:
<pre>
cat /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq
</pre>

=CPU temperature=
i.MX8M-Plus SoC features an internal temperature sensor which allows to measure the SoC temperature.
Execute the following command to read the current CPU temperature:
<pre>
cat /sys/class/thermal/thermal_zone0/temp
</pre>

=RTC=
There two rtc on the device:

==rtc0 (snvs-rtc-lp)==
* System information
<pre>
udevadm info -p /sys/class/rtc/rtc0

P: /devices/platform/soc@0/30000000.bus/30370000.snvs/30370000.snvs:snvs-rtc-lp/rtc/rtc0
N: rtc0
L: -100
S: rtc
E: DEVPATH=/devices/platform/soc@0/30000000.bus/30370000.snvs/30370000.snvs:snvs-rtc-lp/rtc/rtc0
E: DEVNAME=/dev/rtc0
E: MAJOR=251
E: MINOR=0
E: SUBSYSTEM=rtc
E: USEC_INITIALIZED=8188223
E: DEVLINKS=/dev/rtc
</pre>

* Wake up:
This rtc can be used as a wake up source, as a result an '''rtcwakeup''' can be used with this device:
<pre>
rtcwake --device /dev/rtc0 -s 5 -m mem
</pre>

==rtc1 (ab1805)==
* System information
<pre>
udevadm info -p /sys/class/rtc/rtc1

P: /devices/platform/soc@0/30800000.bus/30a30000.i2c/i2c-1/1-0069/rtc/rtc1
N: rtc1
L: 0
E: DEVPATH=/devices/platform/soc@0/30800000.bus/30a30000.i2c/i2c-1/1-0069/rtc/rtc1
E: DEVNAME=/dev/rtc1
E: MAJOR=251
E: MINOR=1
E: SUBSYSTEM=rtc
</pre>

* Set the date and write it into the RTC:
<pre>
date -s "12 SEP 2019 10:00:00"

Thu Sep 12 10:00:00 UTC 2019
hwclock --systohc --rtc /dev/rtc1
</pre>

* Read the RTC time and date:
<pre>
hwclock --show --rtc /dev/rtc1

Thu Sep 12 10:00:48 2019  0.000000 seconds
</pre>


= Device Serial Number=
Product information is stored in on-board EEPROM.<br>
* To read the product serial number, issue the folowing command:
<pre>
cat /proc/device-tree/product-sn
</pre>
* To read the product configuration part number, issue the following command:
<pre>
cat /proc/device-tree/product-options
</pre>

=See Also=
*[[MCM-iMX8M-Plus: Evaluation Kit: Getting Started | MCM-iMX8M-Plus:Evaluation Kit: Getting Started]] <br>

[[Category:Yocto]]
[[Category:MCM-iMX8M-Plus]]