The OKMX6ULL-S single board computer adopts NXP's high-performance, ultra-efficient, low-cost development design, and adopts advanced ARM-core. The SBC adopts 4.1.15+QT5.6 operating system, supports two configurations of industrial grade and commercial grade: 256MB DDR3L/512MB DDR3L, 256MB NandFlash/4GB eMM, supports OTG, SD/TF card batch programming supports single-step Update the kernel.

OKMX6ULL-S SBC Block Diagram

Comparison of imx6ul SoM and imx6ull SoM

	FETMX6UL-C SoM	FETMX6ULL-S SoM
CPU	NXP i.MX6UL	NXP i.MX6ULL
Architecture	Cortex-A7	Cortex-A7
Frequency	528MHz	800MHz
RAM	512MB LvDDR3L	256MB DDR3L/512MB DDR3L
ROM	256MB/1GB NAND FLASH, 4GB eMMC	256MB NandFlash / 4GB eMMC
Interface	board to board connector	stamp hole
Dimensions	50mm* 40mm	35mm*44mm
SD/MMC/SDIO	2-ch	2-ch
Camera	1-ch DVP	1-ch 8-bit DVP
UART	8-ch	8-ch, up to 5.0Mbps
Ethernet	2-ch, 10/100Mbps	2-ch, 10/100Mbps
PWM	8-ch	8-ch, 16-bit
ADC	10-ch	10-ch, 12-bit ADC
Temperature	-40℃ ~ +85℃/ 0℃ ~ +70℃	0 ~ +70℃/ -40℃ ~ +85℃

Compared with FETMX6UL-C, the biggest improvement of FETMX6ULL-S is that its main frequency is increased from 528MHz to 800MHz.

The higher the main frequency, means that the CPU can execute more cycles per unit time. More executable clock cycles mean that the CPU can execute more instructions per unit time. The available system resources are correspondingly more.

In general, the higher the main frequency, the higher the system speed.

By viewing the /proc/cpuinfo file, you can get information such as CPU:

The CPU information of i.MX6UL is as follows:

root@imx6ulevk:~# cat /proc/cpuinfo Processor : 0 model name : ARMv7 Processor rev 5 (v7l) BogoMIPS : 3.00 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xc07 CPU revision : 5 Hardware : Freescale i.MX6 Ultralite (Device Tree) Revision : 0000 Serial : 262589d4ee6c5c1d

The CPU information of i.MX6ULL is as follows:

root@fl-imx6ull:~# cat /proc/cpuinfo processor : 0 model name : ARMv7 Processor rev 5 (v7l) BogoMIPS : 3.00 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xc07 CPU revision : 5 Hardware : Freescale i.MX6 Ultralite (Device Tree) Revision : 0000 Serial : 0000000000000000

In order to reflect the difference between the two due to the main frequency band, the following two tests are performed:

1, Hard floating-point test

The following is a test. The content of the test program is to let the single board computer perform 1 billion addition, subtraction, multiplication and division operations. Compile the test program and transplant it into FETMX6ULL-S and FETMX6UL-C respectively, and run the hard floating point program on the two corresponding development boards respectively. The test procedure is as follows:

#include intmain() {    floata = 0.3f, b=1.0f;     longi;    for(i=0;i <1000000000;i++)    {       a = a*b;        a = a/b;        a = a+b;        a = a-b;   }    printf("success ok\n");    printf("%f\n", a * b);   return0; }

The FETMX6UL-C hard float time is 1 minute 33 seconds 65, while the FETMX6ULL-S hard float time is 1 minute 02 seconds 45.

It can be seen that the same number of addition, subtraction, multiplication and division operations are performed, and the FETMX6ULL-S is nearly 30 seconds faster than the FETMX6UL-C, so the biggest manifestation of the high frequency of the FETMX6ULL-S is that it runs faster.

2, CPU usage when playing the same video

Download a 480p video as a test material. Adjust the frequency of the OKMX6UL-C and OKMX6ULL-S sbc to the maximum.

1. All cpufreq governor types supported in the current kernel:

root@freescale/$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors

Serial output is:

conservative ondemand userspace powersave interactive performance where userspace represents user mode, in which other user programs are allowed to adjust the CPU frequency.

2. Check the frequency range supported by the current CPU:

root@freescale/$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

Serial output is:

198000 396000 528000

3. Set to user mode with the highest modification frequency:

root@freescale/$ echo userspace > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
root@freescale/$ echo 528000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

4. View the current frequency:

root@freescale/$ cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq

Serial output is:

528000

The above process takes FETMX6UL-C as an example. The maximum frequency of FETMX6UL-C can be set to 528000, and the maximum frequency of FETMX6ULL-S can be set to 792000.

Second, put the download test videos into the development board and play them.

mplayer-fs -vo fbdev /run/media/mmcblk0p1/t21.mp4

Query the CPU usage during playback, and you can get the results shown in the following figure:

CPU usage of FETMX6UL-C:

CPU usage of FETMX6ULL-S:

According to the data in the figure, the CPU occupancy rate of FETMX6UL-C is 99%, while the CPU occupancy rate of FETMX6ULL-S is 68%.

It can be seen that the occupancy rate of the FETMX6ULL-S is lower, so the energy consumption is lower.

From the above two tests, it can be concluded that because the main frequency of FETMX6ULL-S is higher than that of FETMX6UL-C, its performance is also better than that of FETMX6UL-C. At the same time, the connection method between the FETMX6ULL-S SoM and the bottom plate is adopted, which takes up less space, saves more space, reduces costs, and is more suitable for use in high-salt and high-humidity environments. However, because the FETMX6ULL-S adopts the stamp hole design, the system on module and the single-board computer are integrated, so the flexibility is worse than the FETMX6UL-C series designed with board-to-board connectors.

The SoM/SBC of the i.MX6 series has been launched for a long time, and the product information and maturity are more, and the experience of successful solutions is also richer. You can choose a single board computer that better meets your requirements according to your own needs.