[Retracted] Secure Internet of Things Gateway Technology Based on Multicommunication Methods

Table 4

Other circuit descriptions of the minimum system of the gateway platform.

Circuit name	Illustrate
Clock circuit	The system has two clocks, one is for CPU and other circuits, using 13 M active oscillator, and the other is RTC dedicated timing clock, built with 32.768 K active clock.
NandFlash	As a system boot chip, it stores the bootloader of the Linux operating system, the kernel, and the file system. After the system is powered on or reset, the commands are obtained from the first address and executed sequentially. The system uses the NanclF flash model K9F1G0suoc-PCBO with a capacity of 1 GB.
Mobile DDR	SRAM is static RAM with extremely high read and write speed. It is used for variables, data and buffering in the system, and programs can also be copied to SRAM to run, in order to improve the system efficiency, but it is a volatile storage, the data will be lost when power off, so it cannot boot the program to run. This system expands two pieces of SRAM, the model is K4X1G163PE-FGC6, the capacity is l28 MB, and the frequency is 130 MHz.