The virtual oscilloscope combines the computer's powerful computational processing capabilities with the signal acquisition and control capabilities of general hardware instruments to achieve functions and friendly interfaces that cannot be achieved by general oscilloscopes, making up for the traditional oscilloscope's single-function, bulky, and inconvenient to carry. The lack of price is expensive. With the development of computer technology, the requirements for the intelligence and miniaturization of virtual instruments are increasing. The development of embedded systems makes embedded virtual instruments based on embedded microprocessors and real-time operating systems meet the needs of portable virtual instruments in harsh working environments. At the same time, the USB-based instrumentation overcomes the deficiencies of the existing PC bus virtual instrument and can meet the requirements of automated industrial measurement, and is particularly suitable for on-site signal testing. Commonly used virtual instruments mostly use PCI or ISA slots. However, the number of capture cards is generally limited. Therefore, when setting up a system, only specific computers or embedded dedicated capture cards can be specified. However, some devices do not support PCI or ISA at all. Bus, this built-in form is easily affected by high-frequency interference in the PC chassis, reducing the system's sampling accuracy and stability. If the entire system can be made into an external type, not only can improve the system's sampling accuracy and stability, but also enhance the flexibility of the system, but also conducive to the maintenance of the system. The USB interface is a more convenient, more effective and more flexible bus communication type for implementing virtual instruments. The USB bus is a new generation bus technology that enables the PC to configure new hardware devices without opening the cover and supports hot-plugging technology, giving users great convenience. USB bus has the characteristics of high transmission rate, support for asynchronous and isochronous transmission, and can connect 127 independent USB devices at the same time. It is suitable for outboard high-speed, high-precision sampling systems. USB technology is a non-profit specification and has received extensive industry support. The embedded processor is made up of C8051F020 one-chip computer and USB bus chip CH375. The C8051F020 microcontroller acts as the system's CPU for logic control, data acquisition, and storage management. It receives the data source signals uploaded from the test analysis object and collects data in real time through control functions such as signal conditioning modules and analog-to-digital conversion modules. The USB bus chip CH375 As the interface with the host computer to communicate data to the host computer monitoring module. The system structure is shown in Figure 1. The C8051F series single-chip microcomputers are fully integrated mixed-signal system-level chips and have a 8051-compatible controller core and are compatible with the MCS-51 instruction set. On-chip integrated analog components and other digital components commonly used in data acquisition and control systems are also integrated. Set up and functional parts. The C8051F microcontroller adopts a pipeline structure. The machine cycle is reduced from the standard 12 system clocks to 1 system clock. The processing capability is greatly improved and the peak performance can reach 25M. IPS.C8051F is a system-on-chip (SoC) that can work independently. Each MCU can effectively manage analog peripherals and digital peripherals, turning off individual or all peripherals to save power. Flash memory also has on-chip reprogrammability that can be used for nonvolatile data storage. On-chip JTAG debugging supports observation, modification of memory and registers, support for breakpoints, single-step, run, and shutdown commands. All analog and digital peripherals are fully functional when debugging. The most prominent improvement of the C8051F is the introduction of digital crossbars. This is a large digital switch network that allows internal digital system resources to be allocated to port I/O pins. This structure can support all combinations of functions. The on-chip counter/timer, serial bus, hardware interrupt, ADC conversion enable input, and other digital signals internal to the microcontroller can be configured on the port by setting the cross-switch control register. The I/O pin, which allows the user to select a combination of general-purpose port I/O and required digital resources based on their specific application. USB module CH375 is a universal device interface chip of USB bus. It does not need to write drivers. It has a built-in underlying protocol in USB communication and fully meets the USB1.1 standard. The module has 8-bit data bus (D0 ~ D7), address input (A0), read (RDJHJ), write (WRJHJ), chip select control line (CSJHJ), and interrupt output (INTJHJ) and other functions, you can easily hang Received the one-chip computer data bus. The data port is selected when A0 is low and the microcontroller reads and writes data to the CH375 through the 8-bit parallel port. When the AO is high, the command port is selected and commands can be written to it. At the local end, the operation of the single-chip microcomputer on the CH375 is the command-plus-data I/O operation mode. Any operation is the first command to the CH375, and then the data input/output is performed. After receiving the data sent by the upper computer or sending the data to the upper computer, the CH375 notifies the microcontroller in an interrupt mode. The USB module CH375 of each channel provides an end-to-end connection between the computer application layer and its local MCU, and adopts the data plus response mode to communicate. All communications are initiated by the computer application layer, and then the response to the MCU is completed. . 6Gang Switch And Multi Function Socket 6Gang Switch And Multi Function Socket,6Gang Switch,Multi Function Socket,Multi Function Socket Wrench ZHEJIANG HUAYAN ELECTRIC CO.,LTD , https://www.huayanelectric.com