Multi-functional intelligent socket USB interface communication circuit design

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Existing sockets have shown a variety of trends in terms of their use, function and shape characteristics. Some have added insurance functions, power indication functions, and switch functions, and some have added voltage regulation functions. In any case, the functions of these sockets can only be used for a single purpose: to provide a power interface for the consumer. Their common shortcoming is that they do not have information and intelligence. In order to realize the informationization and intelligence of the socket, we will study the intelligent information system designed and integrated with the socket, and integrate the smart device with the power socket to design a multifunctional intelligent monitoring socket. The socket is fixed once in the electrical installation of the building, and is powered by the lighting power source. When people use it, it is like using a normal power socket, which eliminates too many cables.

Interface chip and its working principle

In this article we use the PDIUSBD12 chip from Philips, an inexpensive, full-featured parallel interface chip that supports multiplexed, non-multiplexed, and DMA parallel transfers. The PDIUSBD12 interface chip complies with the protocol USB1.1 and is suitable for different types of transmission types. PDIUSBD12 requires an external microcontroller (MCU) for protocol processing and data exchange. It has no special requirements for MCU, and the interface is convenient and flexible. Therefore, designers can choose the MCU that they are familiar with to control the chip, and also use the firmware of Philips. Structure to reduce development time, reduce risk, and reduce investment.

Performance characteristics: In addition to the general characteristics of USB devices, PDIUSBD12 has the following features: (1) It is a high-performance USB interface chip, which integrates SIE (Serial Interface Engine), 320-byte FIFO, and transceiver. And voltage regulator. (2) Applicable to most equipment class specifications. High-speed parallel interface with any external microcontroller/microprocessor at speeds up to 2Mbit/s, and (3) fully independent DMA operation. (4) The primary endpoint is configured with double buffering, which can improve data throughput, reduce data transmission time, and easily realize real-time data transmission. (5) When the synchronous transmission mode is adopted, the data transmission speed is 1 Mbit/s; and the speed of the bulk transmission method is 1 Mbyte/s. When using the above method for data transmission, a variety of interrupt methods can be conveniently used. (6) With programmable clock output, the connection to the USB bus can be controlled by software (Soft Connect TM). (7) There are two operating voltages to choose from: 3.3 ± 0.3V and 3.6 ~ 5.5V. (8) The output and data transmission status can be monitored by the USB connection indicator.

Communication hardware circuit design

In this paper, we use 89C52 microcontroller as the microcontroller of the system. The circuit connection of PDIUSBD12 and 89C52 is shown in Figure 1:

Figure 1 USB interface communication circuit

Conversion card circuit design

The design includes microcontroller software (firmware) design and host part software design. The MCU software is developed using WAVE simulation software provided by Weifu, and is debugged online through its simulator. The host part software includes two parts, a driver and an application, which are generated using DDK and VC6.0 respectively.

Figure 3 USB interface conversion card circuit diagram

The research on the intelligent monitoring socket is still in the theoretical imagination and design process. There is still a long way to go to make products, and more people need to put more energy into it. Especially with the USB communication, the writing of the USB driver is a difficult point. With the continuous updating, improvement and development of technology, it is believed that the implementation of the multi-function socket will become easier.