Thanks to EE and the manufacturer's trial activities, I got the board for almost half a month, and finally I had some free time to play with the so-called first NXP processor with NPU. The core chip of MYD-JX8MP is MIMX8ML8CVNKZAB/MIMX8ML8DVNLZAB, which is based on the high-performance quad-core ArmCortex-A53 64-bit RISC core, with a commercial-grade frequency of up to 1.8GHZ and an industrial-grade frequency of 1.6GHZ. Each CPU core of the Cortex-A53 processor includes a 32 kbyte L1 instruction cache, a 32 kbyte L1 data cache, and a 512kbyte secondary cache. The device also embeds the Cortex-M7 32-bit RISC core, which can operate at a maximum frequency of 800MHz. The core function of the Cortex-M7 is a single-precision floating-point unit (FPU), which supports Arm single-precision data processing instructions and data types. The Cortex -M7 supports a complete set of DSP instructions and a memory protection unit (MPU) to enhance application security.
View system version information:
cat /proc/version
Read CPU information:
cat /proc/cpuinfo
Get CPU temperature information:
There is a TMU inside the CPU chip to detect the CPU temperature, and the temperature measurement range is -40~125℃.
cat /sys/class/thermal/thermal_zone0/temp
The displayed number is one thousandth of a degree and needs to be divided by 1000 to get the current temperature value, which is currently 26℃.
Check the CPU operating frequency:
CPU operating frequency The CPU supports dynamic frequency adjustment and fixed frequency, and the 4 A53 cores operate synchronously.
cat /sys/bus/cpu/devices/cpu0/cpufreq/cpuinfo_cur_freq
View memory information:
The default memory of MYD-JX8MP is 3G, and the system divides the memory into device memory (CMA) and system memory (MEM).
cat /proc/meminfo
Get memory usage:
Use the free command to read the memory usage. The -m parameter represents the unit in MByte.
free -m
Memory stress test:
The memtester tool that comes with the kernel can test the system's existing memory by giving the size and number of test memory.
memtester 300M 1
View eMMC capacity:
MYD-JX8MP is equipped with an 8G eMMC. The eMMC partition information and capacity can be queried through the fdisk -l command.
fdisk -l
/dev/mmcblk2p1: used to store kernel and dtb files
/dev/mmcblk2p2: used to store the file system. Here /dev/mmcblk2p1 starts at block 20480, and the bootloader and partition table information are also stored in the front.
View eMMC partition information:
The df command can be used to query eMMC partition information, usage, mount directory and other information.
df -h
/dev/root : Root file system, mounted to the root directory.
tmpfs: Memory virtual file system, mounted to different directories.
devtmpfs: used to create dev system.
/dev/mmcblk2p1: used to store kernel and dtb files, mounted in the /run/media/mmcblk2p1 directory by default.
eMMC performance test:
The performance test mainly tests the reading and writing speed of files by eMMC under Linux system. The test is carried out by combining time and dd commands.
Write file test
time dd if=/dev/zero of=tempfile bs=1M count=100 conv=fdatasync
When using the dd command to write files, you need to add the conv=fdatasync parameter, which means that after dd finishes writing N times, the cache will be flushed and synchronized to the disk.
Read file test
To ignore the effect of cache when reading files, specify the parameter iflag=direct,nonblock.
time dd if=tempfile of=/dev/null bs=1M count=100 iflag=direct,nonblock
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