Design and implementation of cloud computer system based on RK3588

Cloud computing is a comprehensive service solution that includes cloud resources, transmission protocols, and cloud terminals. Using open cloud terminals and transmission protocols, desktops, applications, hardware and other resources are provided to users in an on-demand, elastically allocated service model. Users do not need to consider building complex IT to achieve single-machine multi-user.

Compared with traditional computers, cloud computer boxes do not have CPU, memory, hard disk and other hardware inside. These hardware are in the cloud, which enables hardware resource sharing and on-demand allocation. The cloud computer system designed in this paper is exquisite and compact, easy to carry, quick to deploy and simple to operate; after connecting to the network, mouse, keyboard and display, you can access your personal desktop, data and various applications.

1. Whole machine system solution

The overall system solution adopts Rockchip RK3588 as the main control, and Realtek RTL8822CU as the Wi-Fi. After the system is powered on, connect the mouse and keyboard, and connect to the display via HDMI, and it can be used as a normal computer. The overall system architecture of the cloud computer is as follows:

Figure 1 Cloud computer system architecture

2 Hardware System Design

The hardware system uses Rockchip RK3588 as the main control, and Realtek RTL8822CU as the WIFI. Rockchip RK3588 is an 8K flagship chip, using ARM architecture, 8 nm advanced process, integrated with 8-core 64-bit architecture, up to 32 GB of large memory, supports 8K video encoding and decoding, and has the characteristics of high performance and low power consumption. Realtek RTL8822CU is a highly integrated dual-band Wi-Fi + Bluetooth 5.0 2T2R SDIO3.0 module. It supports 802.11n 2.4 GHz or 5 GHz dual-band MIMO and 802.11acwave-2 MU-MIMO, is backward compatible with IEEE 802.11a/b/g/n/ac standards, and provides a maximum PHY data rate of 867 Mbit/s. The host interface complies with the wireless LAN SDIO 1.1/2.0/3.0 standard, with a clock rate of up to 208 MHz. BT uses the HS-UART interface, includes Bluetooth V2.1/3.0/4.1/4.2, and supports Bluetooth 5.0 system.

The hardware system mainly includes: power module, clock, reset, DDR, EMMC, Wi-Fi circuit, USB interface, HDMI interface, and network port circuit. The power module, clock, reset, DDR, and EMMC ensure the normal operation of the system; the Wi-Fi circuit ensures that the system can be connected to the Internet through a wireless network, and the network circuit ensures that the system can be connected to the Internet through a wired network; USB connects the mouse and keyboard to ensure the interaction between people and cloud computers; HDMI connects the display screen to display the user operation screen in real time. The hardware system block diagram is as follows.

Figure 2 Hardware system block diagram

The RK3588 chip has two PLL power supplies, namely PLL_AVDD_1V8 and PLL_AVDD_0V8. To prevent interference with the PLL power supply, the coupling capacitor must be placed close to the pins and powered by a separate LDO. The power supply capacity of the power chip LDO that powers the chip Logic and NPU power supply is greater than 2 A, otherwise the system will be unstable. The 24 MHz crystal oscillator and the internal feedback circuit together constitute the system's clock circuit. The chip's nPOR pin is valid at low level and is used to reset the chip. The reset time is greater than 4 μs to ensure stable operation of the chip. The XIN and XOUT signals of the crystal oscillator are grounded during the PCB design, and these signals are guaranteed to have a complete reference ground. The power line or high-speed signal cannot pass under the crystal circuit, and there are no more than two vias. The crystal oscillator is placed close to the main control. Different signal lines within a DDR group and adjacent signal lines between groups must follow the "3W" principle. The line length error of the CLKP and CLKN differential pairs is less than 5 mil, the line length error of DQS, DM and DATA is less than 10 mil, and the line length error of the DQSnP and DQSnM differential pairs is less than 5 mil. FLASH keeps the signal reference plane intact to avoid signal routing through the power segmentation area, and the spacing between adjacent signal routings follows the "3W" principle.

3 Cloud Computer System Signal Processing Process

In terms of signal processing, in addition to supporting hardware peripherals, the core content of cloud computers is mainly to process cloud data. Therefore, in the core system solution, the cloud data processing process is as follows:

Figure 3 Cloud data processing flow

The image mode is used when the frequency of image changes in the cloud computer is low. The entire cloud desktop is a large bitmap. Whenever the image changes, only the data of the changed area is transmitted to the client in RGBA format, and then the client updates the data of the changed area in the large image accordingly. The streaming mode is used when the frequency of image changes in the cloud desktop is high. In this mode, the entire desktop image is encoded with the h264 protocol and transmitted to the client, and then the client uses mediacodec to decode and render it to the surface.

4 Conclusion

This article designs a cloud computer system based on RK3588, which is exquisite and compact, easy to carry, quick to deploy, simple to operate, and has a very broad market prospect.