Cortex-m3-based Real-time Data Acquisition System ¦Ìc/os- ¢ò And Can Bus

In recent years, Data collection systems are widely used in the fields of engineering construction, scientific research, control, and so on. The real-time and process speed is demanded in these fields and the cost is controlled very strict. Cortex-M3 kernel form ARM Company meets these needs. The paper realizes real-time data acquisition system on a Cortex-M3 processor.Base on the STM32F103VC chip which integrates Cortex-M3 kernel, our system completes the acquisition to the analog signal data outside. And after the filter processing, the collected data ultimately is transferred to another development board to undertake handling through the CAN bus communication. The STM32F103VC chip is designed to a high-performance, low-cost, and low-power embedded processor. Its characteristics are high-level integration and easy development. The basic expand control area network (bxCAN) is integrated into the STM32F103VC chip. So we can only add a TI SN65HVD230 as transceiver to realize the CAN bus communications.Now, the Data collection systems are very complicated. One infinite loop application cannot already satisfy the demand. This paper adopts theμC/OS-Ⅱreal-time embedded operating system for data acquisition task management. The real-time performance of u C/OS-II is very good and it doesn't need the development costs. About theμC/OS-II operating system, this paper illustrates the transplantation of theμC/OS-II real-time operating system on the STM32F103VC chip, and gives the code changes of each file.In software, the paper respectively expounds the ADC module and data collection, design and expansion of the real-time communication CAN bus development. The ADC module adopts STM32F103VC chip integrated pieces analog/digital converter (ADC), and transmits data through the DMA mode to reduce the use of CPU resources. This gives full play to the real-time performance of the Cortex-M3 chip. And the data collected will filter processing firstly. This paper is using the median value average filtering method. About the CAN bus module, the STM32F103VC chip integrates field bus communication interface (bxCAN). The bxCAN supports CAN 2.0A and current CAN 2.0 B standard interfaces fully compatibly. For the CAN bus, the paper gives the initialization, baud rate setting, filter Settings and the detailed code design of sending message. TheμC/OS-Ⅱoperating system manages ADC module and the CAN bus module.