![]() ![]() num=xxxĮcho out > /sys/class/gpio/gpio$/value Note that pinmux may need to be set in advance. Subject to the labeling of the document, the silkscreen labeling of the internal test version may be incorrect The GPIO correspondences of the pins on the LicheePi 4A are(from the perspective of overlooking the front of the BOTTOM plate, TOP is the left side, BOTTOM is the right side): Where the 4Byte (32bit) at offset 0x0 is the GPIO data register and the 4Byte (32bit) at offset 0x4 is the GPIO direction register. The TH1520 SOC has 4 GPIO banks, each with a maximum of 32 IOs: Bank The serial input side on the pins has been processed with 1/2 voltage divider and can be connected to a 3.3V serial port. Note: All native IOs of the SOC are at 1.8V level, please pay attention to the level shift. The LicheePi 4A has 2x10pin pins on board with 16 native IOs, including 6 normal IOs, 3 pairs of serial ports, and one SPI. Take PWM1 which is connected to the cooling fan as an example, you can enable the fan with the following code: echo 1 > /sys/class/pwm/pwmchip0/exportĮcho 1000000 > /sys/class/pwm/pwmchip0/pwm1/periodĮcho 1000000 > /sys/class/pwm/pwmchip0/pwm1/duty_cycleĮcho 1 > /sys/class/pwm/pwmchip0/pwm1/enable Sudo cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq PWM If it boots successfully, then you can check the following values to confirm that it has been successfully overclocked: Note that there is a chance that it will not boot after this modification, and then you need to re-burn the firmware to recover. Here is a simple overclocking procedure for reference only, no guarantee for stability and safety.Ĭheck the files under /boot: fw_dynamic.bin #opensbiĬopy light-lpi4a_2Ghz.dtb and overwrite it with light-lpi4a.dtb, reboot, and then you can change the maximum frequency after booting. The TH1520 runs at 1.85GHz by default, but preliminary tests show that about 80% of the chips can run at 2GHz, and about 50% of the chips can pass the stress test at 2GHz. ![]() ![]() Chip temperatureĬat /sys/class/thermal/thermal_zone0/temp Please maintain good heat dissipation to keep the CPU below 60 degrees for optimal performance. Note that the system comes with a temperature control policy that will downclock the system when it is too idle or too hot. Sudo cat /sys/devices/system/cpu/cpu*/cpufreq/cpuinfo_cur_freq ![]()
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