Expanding Functionality in Industrial Control Boards via USB

As an excellent engineer, you have experienced countless battles and seen numerous boards! Please wake up, a new project has arrived, this is a product requirement that needs to have, and also needs to have, and still needs to have. How can a processor achieve such a rich set of peripheral interfaces? In hesitation, you stumble upon this article. Thus, the “Pandora’s box” is opened!

Indeed, USB resources are the key to unlocking a new world. What expansions can it achieve?

1.1 USB Network Port Expansion

Most general ARM processors come with two network ports. If the project requires multiple network interfaces, it is common to add a switch/router externally. Of course, for cost considerations, the switch chip can also be integrated into the ARM core board or baseboard, such as KSZ9897, YT9215, etc. However, if you need the expanded network port to have completely independent MAC addresses and controlled costs, expanding via USB is also a good choice.

Figure 1 Multi-port network card

Common USB network expansion chips include LAN9730, AX88179, RTL8211, etc., which can be selected based on the situation to expand 100M or 1G network ports via USB2.0 or USB3.0.

1.2 USB WiFi Expansion

This is a relatively common usage method. Common WiFi modules reserve communication interfaces such as USB, SDIO, UART/SPI. For some chips with limited SDIO resources, expanding WiFi functionality via USB seems logical, and USB can meet higher communication rates. Models like RTL8821, RTL8188, etc. are relevant.

Figure 2 Common WiFi modules

1.3 USB SATA Expansion

Most mid-range and low-end processors do not support SATA or PCIe buses. If large-capacity external storage is needed, expansion must be considered. Yes, inserting a TF card externally can meet most usage requirements, but if you have certain requirements for communication speed and a large demand for storage capacity, please pay attention to using USB to expand SATA solutions like SPIF225A, JM20329, PL-2571. It should be noted that due to chip selection and circuit design, the transmission speed of this solution is still limited.

1.4 USB Serial Port Expansion

This kind of demand is also relatively common in the industrial field. Products like data collectors and communication managers often require more than 10 RS232/RS484 connections. Besides the common SPI expansion of UART, expanding through USB is also a good route. Chips like CH9344, CH348, FE1.1S are commonly used and can be reasonably selected based on demand.

1.5 USB SPI/IIC Expansion

This expansion method may not be commonly used for MPUs, as the number of SPI/IIC resources is usually sufficient for most scenarios. If there is a need, it is recommended to refer to CH347, a high-speed USB bridge chip that can achieve USB to SPI, USB to I2C, USB to JTAG, and other functions.

1.6 USB Expansion for USB

Clearly, since USB is so useful, there will be situations where the quantity is insufficient. Expanding USB is a common USB HUB solution, such as 4/6/8 port HUB chips. Additionally, HUB chips can easily achieve cascading expansion. When expanding multiple ports using the HUB solution, be sure to pay attention to speed bottlenecks. Here, refer to USB2514, FE1.1, USB5744, etc.

Modules like 4G modules, USB cameras, touch screen signals, etc., are also realized through USB communication. Therefore, it can be seen that the USB interface is truly an expansion master in our industrial control field. However, if the cost budget is sufficient, it is still recommended to choose processors with rich peripheral resources. After all, native resources are the most reliable for ensuring stability and performance.

We focus on the design and production of embedded ARM hardware and software, and we welcome developers to communicate and exchange ideas anytime!

·END·

Wanxiang Aoke

Embedding a Beautiful Life