USING OF THE NIOS II CORE IN A MULTI-CHANNEL FREQUENCY COUNTER ON FPGA FOR A RADIO ENGINEERING SYSTEM WITH FREQUENCY SENSORS OF PHYSICAL QUANTITIES

Abstract

The paper presents one of the ways to expand the functionality of the multi-channel parallel frequency measurement system based on the Altera Cyclone IV FPGA, the main task of which is to measure the informative parameter of sensors of physical quantities with frequency output, using the NIOS II microprocessor core. An improved multi-channel universal measuring device based on FPGA, which has 12 measuring channels for sensors with frequency output. The blocks of the pulse counter, data processing, UART transmitter were partially reworked, Nios II was generated and configured, the circuit was re-synthesized. Integration of NIOS II into a multi-channel frequency meter will make the system more flexible, add pre-processing, filtering of received data and change the number of frequency meters, without changing the data processing algorithm, which is impossible in the previous implementation of the system. When introducing a frequency meter, a microprocessor system into the scheme, part of the tasks from the existing blocks are transferred to a more flexible component - the microprocessor. Such blocks as: data processing from counters, UART transmitter, completely lose their relevance, they will be implemented by means of the processor. The pulse counter unit will be partially redesigned for ease of use with a microprocessor system. Software has also been developed that allows to read data from frequency meters, process, convert and transfer them to the UART serial port. Since after the integration of the NIOS II core reading frequency and transfer to the UART port is done programmatically, it is possible to implement the algorithm that will convert the read frequency value into the physical value of the sensor.