Design Of Program-Controlled Digital Storage Oscilloscope

With the development of the electronic measuring technology, measuring technology is geared to automated, intelligent and network directions. Digital storage oscilloscope as the important measuring apparatus is widely used in various fields. Now the technology of digital storage oscilloscope is more advanced overseas, and occupies the great majority of market. So it is indispensable to develop digital storage oscilloscope ourselves.In this subject, we adopt ARM+FPGA structure. We will discuss these correlative problems based in this structure. The system includes two sub-systems: data acquiring system and data processing system. The data acquiring system is the key of the design of digital storage oscilloscope, it completed the conversion from analog signal to digital signal , that is analog signal enter in the A / D through conditioning channel and convert into digital signal, then these figures are deposited in buffer RAM. The digital processing unit based in the ARM processor acts the most important character in the data processing system. The main job of the data processing system is reading acquired data from buffer RAM, processing and calculation. The acquired data will show on the LCD as a wave.The main attributions of the paper include:1. The design of the data acquiring system. The data acquiring system is the key of the oscilloscope,which converts analog signal to digital signal. At first the primary grade level attenuation signal amplifier makes the signal in the conformable range. Then the signal will be transmitted to the ADC unit. The signal which finishes Analog-to-Digital conversion will be store in the dual-port RAM. 2. The design of ARM controller system. The ARM microprocessor system is the key of the data processing system, which connects the data-processing system and LCD module. It plays as an important role in the overall system. There are several tasks the ARM microprocessor system has to do: Recover the acquired data into waveform and display it on the LCD; Response to the Interruption of the keyboard; Analysis the key words and then change the menu on the LCD; Send control signals to the data acquiring system and control the data acquiring speed; It is also responsible to the serial communications.3. The design of LCD control circuit. Based in the S3C44B0X embedded LCD controller, we drive a 256 level color LCD module. The screen' size is 320×240 dots. The LCD controller has dedicated LCDCDMA, which supports to fetch the image data from video buffer located in system memory.4. The design of serial communication interface. Based in the S3C44B0X embedded UART, we can communicate with PC through the MAX3232 asynchronous serial transceiver.The system is based on the structural design of shared memory with ARM + FPGA systems architecture. There are two features in the system: ARM processor's low cost and the FPGA' flexibility. Based on the shared memory structure, the data from the high-speed ADC can be stored in the system's memory directly. The efficiency of data acquisition is significantly improved. To the design of low-cost, relatively high performance digital storage oscilloscope products, the paper has made a useful attempt. And the design makes some achievement for further research.