The MBa93xxCA provides the CAN interfaces CAN0 and CAN1.
DIP switchs S4 and S5 are used to configure the CAN interfaces CAN0 and CAN1.
Function | S4-1 | S4-2 |
---|---|---|
CAN-Bus not terminated | OFF | OFF |
not defined (illegal state) | OFF | ON |
not defined (illegal state) | ON | OFF |
CAN-Bus terminated with 120 Ohm | ON | ON |
Function | S5-1 | S5-2 |
---|---|---|
CAN-Bus not terminated | OFF | OFF |
not defined (illegal state) | OFF | ON |
not defined (illegal state) | ON | OFF |
CAN-Bus terminated with 120 Ohm | ON | ON |
ip link set can0 down ip link set can0 up type can bitrate 500000 sample-point 0.75 dbitrate 4000000 dsample-point 0.8 fd on ip link set can1 down ip link set can1 up type can bitrate 500000 sample-point 0.75 dbitrate 4000000 dsample-point 0.8 fd on
candump can0& cansend can1 5A1#11.2233.44556677.88
candump can1& cansend can0 5A1#11.2233.44556677.88
The STKa93xxCA supports DVFS (dynamic voltage and frequency scaling, by default the governor ondemand
is set.
Governors are power schemes for the CPU. Only one may be active at a time.
Governor | description |
---|---|
performance | Run the CPU at the maximum frequency. |
powersave | Run the CPU at the minimum frequency. |
userspace | Run the CPU at user specified frequencies. |
ondemand | Scales the frequency dynamically according to current load. Jumps to the highest frequency and then possibly back off as the idle time increases. |
conservative | Scales the frequency dynamically according to current load. Scales the frequency more gradually than ondemand. |
schedutil | Scheduler-driven CPU frequency selection |
You can change the actual governor with the following command:
cpufreq-set -g <governor> (e.g. cpufreq-set -g performance)
At runtime it is possible to disable multiple CPU cores via the Linux sysfs. On a system that has four CPU cores, the maximum of three cores can be disabled.
To disable the a CPU core value 0
must be written to the CPU core specific file /sys/devices/system/cpu/cpu<N>/online
where <N> is the number of the Core, the counting starts at zero.
e.g. disable CPU core 4:
echo 0 > /sys/devices/system/cpu/cpu3/online
To check which CPU core(s) are currently enabled the following command can be used:
grep "processor" /proc/cpuinfo
The CPU core can be enabled again by writing the value 1
to /sys/devices/system/cpu/cpu<N>/online
.
e.g. enable CPU core 4:
echo 1 > /sys/devices/system/cpu/cpu3/online
It is possible to limit the maximium amount of cores with the the maxcpus=
parameter in the kernel command line. To add the new parameter a new U-boot variable addcpu
has to be created.
setenv addcpu maxcpus=${cpu_num}
The amount of cores is set by the cpu_num
variable, for example if cpu num is set to 2
only two cores will be started.
setenv cpu_num 2
The TQMa93xxCA Starterkit provides two Gigabit Ethernet interfaces.
In U-Boot eth0 is configured as default interface. The IP configuration can be done statically or by a DHCP server in the network.
IP configuration via DHCP
For a configuration via a DHCP server, use the dhcp
command in U-Boot.
Static IP configuration For a static IP configuration the following, U-Boot environment variables must be set:
setenv ipaddr <ipaddr> (e.g.: setenv ipaddr 192.168.100.111) setenv netmask <netmask> (e.g.: setenv netmask 255.255.255.0)
Both Ethernet interfaces are activated and configured by systemd-networkd. The configuration files for the interfaces are located in /lib/systemd/network/ these configuration files can be altered to customize the default interface configuration. A documentation of the configuration files can be found here.
eth0 | 10-eth0.network | |
eth1 | 10-eth1.network |
For a temporary static configuration the ip command can be used, below some useful ip commands are listed:
Activate a specific interface
e.g. eth0
ip link set eth0 up
Disable a specific interace
e.g. eth0
ip link set eth0 down
Show ip address for a specific interface
e.g. eth0
ip addr show eth0
Show statistic for a specific interface
e.g. eth0
ip -s link show eth0
Set ip address for a specific interface
e.g. eth0
ip addr add 192.168.1.100/24 dev eth0
Show statistic of all interfaces
ip -s link
Set default gateway for a specific interfaces
e.g. set gateway ip 192.168.1.1 for eth0
ip route add default via 192.168.1.1 dev eth0
If a DHCP server is available in the network environment the ip configuration can be received from it. To do so execute the udhcpc
command, by default eth0 is used.
To configure another interface via dhcp the parameter -i
followed by the interface name e.g. eth1 must be given.
e.g. eth1
udhcpc -i eth1
An overview of the onboard i2c devices is available here
Select i2c bus device
i2c dev 0
Show all devices connected to the i2c bus currently selected:
i2c probe
Detect all devices connected to a i2c bus:
i2cdetect 0
TQ offers an optional LVDS Display kit for the STKa93xxCA. Each Display can be used on its own by using the corresponding device tree. To allow reusage, the support for each display is separated in a dtsi fragment.
To bring up the display the U-Boot environment has to be adapted accordingly.
setenv fdt_file imx93-tqma9352-mba93xxca-lvds-tm070jvhg33.dtb
saveenv
command
To set the hardware clock to the actual time and date use the following commands:
date -s [YYYY.]MM.DD-hh:mm[:ss] hwclock -w
The MBa93xxCA has one SPI interfaces. They can be found on the extension headers and can be tested with a loopback test.
Interface | linux filesystem |
---|---|
SPI6 | /dev/spidev1.0 /dev/spidev1.1 |
For the loopback test you need a bridge between SPI_MOSI and SPI_MISO:
echo -n -e "\x01\x0F" | spi-pipe -d <spi interface> -s 10000000 | hexdump (e.g. echo -n -e "\x01\x0F" | spi-pipe -d /dev/spidev1.0 -s 10000000 | hexdump)
The STKa93xxCA has two temperature sensors, one is located on the TQMa93xxCA SOM and the other is located on the MBa8MPxL baseboard.
Device | I²C Bus | I²C Address |
---|---|---|
TQMa93xxCA | I2C-0 | 0x1C |
MBa93xxCA | I2C-1 | 0x1B |
Read TQMa93xxCA Temperature Sensor
cat /sys/devices/platform/soc@0/30800000.bus/30a20000.i2c/i2c-0/0-001b/hwmon/hwmon0/temp1_input
Read MBa93xxCA Temperature Sensor
cat /sys/devices/platform/soc@0/30800000.bus/30a20000.i2c/i2c-2/0-001c/hwmon/hwmon1/temp1_input
Read CPU internal Temperature Sensor
The i.MX93 CPU has an internal TMU that supports one thermal zones, it can be read by the command below:
Thermal zone0
cat /sys/devices/virtual/thermal/thermal_zone0/temp
With lsusb
you can see all connected usb devices. To mount a partition of an usb stick you can excute mount /dev/<partition> <mount dir>
(e.g. mount /dev/sdb1 /mnt)
. This will mount the first partition of sdb to /mnt. To unmount the device execute umount <mount dir>
(e.g. umount /mnt
).
The MBa93xxCA has two user controllable LEDs, the behavior of these LEDs can be selected by several triggers.
Reference | LED name | color | linux filesystem |
---|
V2 | led1 | green | /sys/class/leds/green |
V3 | led2 | orange | /sys/class/leds/amber |
The user LED's are located in /sys/devices/platform/gpio-leds/leds/.
To change the behaviour a specific LED, the value in the file trigger must be overwritten.
The following values are valid:
For example set the trigger of led2 to heartbeat
echo heartbeat > /sys/class/leds/green/trigger