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This article is presented by:
Shouqian Yu
Lili Yi
Weihai Chen
Zhaojin Wen
Implementation of a Multi-channel UART
Controller Based on FIFO Technique and FPGA
Controller Based on FIFO Technique and FPGA
Abstract:
To meet modern complex control systems communication demands, the paper presents a multi-channel UART controller based on FIFO(First In First Out) technique and FPGA(Field Programmable Gate Array). The paper presents design method of asynchronous FIFO and structure of the controller. This controller is designed with FIFO circuit block and UART (Universal Asynchronous Receiver Transmitter) circuit block within FPGA to implement communication in modern complex control systems quickly and effectively. Form the communication sequence diagrams, it is easily to know that this controller can be used to implement communication when master equipment and slaver equipment are set at different Baud Rate. It also can be used to reduce synchronization error between sub-systems in a system with several sub-systems. The controller is reconfigurable and scalable.
INTRODUCTION
Today, owing to availability of state-of-the-art microcontrollers and digital signal processors (DSPs), complex control algorithms can be easily implemented to attain the desired system performance. But in actual control systems, it is difficult to attain the expected result for various factors affect the control systems such as control algorithms itself, capability of controllers, capability of implement equipment and states of control circumstance [1]. Except those factors, communication parameters of control systems including Baud Rate, BER (Bit Error Rate) and synchronization between sub-systems also engender great effect. In order to improve precision of control system and make good use of modern control algorithms, we should pay much more attention on communication in control systems. In several control systems, UART a kind of serial communication circuit is used widely. A universal asynchronous receive/transmit (UART) is an integrated circuit which plays the most important role in serial communication. It handles the conversion between serial and parallel data. Serial communication reduces the distortion of a signal, therefore makes data transfer between two systems separated in great distance possible [2]. In some complex systems, communications between the master controller and slaver controllers are implemented by serial or parallel port. Parallel communication needs a lot of multi-bit address bus and data bus and it is only convenient for short distance transmission. Serial communication is another way of communication used extensively because of its simple structure and long transmission distance. But sometimes a common serial port could not meet requirements of complex systems with different Baud Rates equipments even some special Baud Rate equipments. As showing in figure 1, in a system, the PC’s Baud Rate is 115200bps and the Ep1 i.e. equipment 1’s Baud Rate is 57600bps, equipment 2’s Baud Rate is 19200bps, and other equipments are set at 9600bps or other Baud Rates. It is impossible to implement this multi-Baud Rate communication system without a special Baud Rate converter.
