Design Of Usb Data Acquisition Card Based On C8051F Mcu Familiy

The data acquisition card is an important part of the computer control system, to achieve communication between sensor, actuator and controller. With its advantage of fast, universal, plug and play, data acquisition card base on USB has become one of the important trends in research of data acquisition card. This paper completes a design of USB2.0data acquisition card which has advantages of high level of integration, feature-rich and high sampling precision.The paper adopts a hardware design based on dual MCU architecture composed by C8051F320and C8051F060.The C8051F060primarily responsible for data collection and the C8051F320for USB communication. The parallel communication between two MCUs is implemented with rapid I/O port and handshake lines. The C8051F060is integrated with a number of peripherals, including two16-bit resolution A/Ds, one eight-channel10-bit resolution A/Ds, two12-bit D/A, multiple timers and counters, the PCA and so on. Software tool for the configuration of the crossbar provide by the vendor is used for early planning and configuration of the input and output pin of above peripherals, which provides a hardware foundation for the feature-rich. The data acquisition card can measure a variety of signal include the analog voltage, the frequency and the digital switch. Also it can output anlog voltage control signal and the PWM wave. High precision measurement of the standard voltage signal of0～5V is implemented as the use of16-bit high resolution A/D on chip. The dual MCU architecture simplifies the structure of the hardware of the system and improves the level of integration. Circuits are designed for the power supply, USB communication, basic working of MCUs. extends of data acquisition card features, parallel communication, signal processing and other communication interface.The dual MCU hardware design also reduces the difficulty of software design which mainly includes the firmware design of dual MCU of the slave device, the USB device driver and the application program on the host computer. Software tool for crossbar configuration is used for generating initialization code quickly. Simultaneous acquisition of multi-channel analog voltage signal with preliminary processing and storage of results is implemented. In accordance with the timing design, parallel communication between two MCUs is completed through the handshake lines. USB device development based on C8051F320is implemented with full use of the USBXpress Development Kit provided by the vendor, which includes the device firmware interface function, host API provided in the form of a Windows Dynamic Link Library and Windows device driver. A test application program on the host computer is designed to display the results of the multi-channel acquisition.Finally, actual running test of the USB data acquisition card designed is made. And acquisition and result display of10-channel analog voltage signal is actually realized with high real-time. According to the theory of polynomial curve fitting, calibrations of errors are done with the help of a high-precision digital multimeter reference. The method is proved to be effective and the errors are significantly corrected.