Instrument Driver Module Based On Embedded Linux System Design

Along with the rapid development of computer science and information technology, embedded technology, one of the best-developed branches of that, gains a wide range of applications in the scientific instrument field.At the beginning of this paper, several common embedded operating systems were analyzed. According to the comprehensive comparison, it was found that open-source Linux system as an advanced, efficient and stable operating system is well suited for developing embedded instrument.Device driver is one of the most important parts for developing software of embedded system. The main contents of this paper are the development of Linux device drivers that are suitable for the embedded Linux instrument, and two kinds of drivers were discussed. The first one is the driver that drives the hardware device inside the local instrument. And the second one is the driver that makes the instrument controlled by PC remotely when the instrument is a unit of the network-integrated test system.In the discussion of the first one, the paper introduced and compared several methods of data transfer between user space and kernel space. Then, combined with the instances of TDR cable test module and power management module in the project of network failure analyzer (NFA), the paper described the usage of proc file system for driver development. The driver module developed with proc file system is clear in structure, easy in use and fit for non-realtime application. The power management module can reduce the power consumption for the portable embedded system. After that, the paper discussed the usage of UIO (Userspace I/O) for driver development, also with the example of DDS waveform generator module in the Arbitrary Waveform Generator (AWG) project. This sort of driver fits for the device of large throughput, realtime or simply reading, writing register and handling interrupt.When discoursing on the remote device driver, the article focused on three aspects, which were USB driver, Ethernet driver and application design. Linux USB Gadget Ehternet is a kernel module that can simulate the USB into the Ethernet interface. With the help of this module, the USB driver can be much simplified and easy-transplanted and can share application with Ethernet remote driver. Application layer program used server and client model as its communication model and defined application layer protocol. TCP/IP protocol was used to ensure the correctness of data transfer on the network and opening of the program framework.So far, all driver instances mentioned in the paper have successfully running in the NFA and AWG, which have successfully passed technical appraisal.