Design And Implementation Of Multi-serial Port Communication Module Based On PCIe Bus

Embedded system is widely used in industrial control, aerospace and other fields with its advantages such as small size and low cost. In embedded systems, the multi-channel data acquisition is an important research direction. The general solution is to collect data from terminals and then upload it to the control center in proper order, but it is difficult to meet the requirements of multi-channel, large quantities of data transmission. With the characteristics of high bandwidth and high stability, PCI Express bus become the hot spot of people chase gradually, which raises the concept of multi-channel serial communication based on PCIe.This subject stems from the development of the next generation medical monitor. In this project, various parameters measurement modules with external wires and probe are used to measure the physiological characteristic parameters of human beings, such as heart sound signal, body temperature and then send data back to industrial computer to display and store.Serial communication is used in multi-channel data transmission. Given the absence of flow control pins in parameters measurement modules, in order to ensure the reliability of communication, a protoco l which blocks the communication between industrial computer and parameters measurement modules should be added in driver. This paper elaborates the frame format, error detection, sliding window and some other details. Having discussed the choice of hardware solutions, this paper adopts the communication card with OXPCIe958 master control chip and external 8-way UART interface chip. After expounding the architecture of teletype layer and UART layer, this paper completes the programming of hardware driver module, and solves the concurrency problems in using hardware or software resources. This paper programs the serial port control class and graphical user interface, which shows the waveform using graphics view framework and stores it. Finally the overall tes t is carried, test environment and results are listed, some analysis and room for improvement is given.After a long time test, the result which includes CPU utilization and transmission rate meets the requirements of indicators. The flow control protocol works properly and the module can correctly complete the work of multi-channel communication, and graphics display is controlled in application layer. So this design provides powerful reference for similar applications in engineering.