FPGA (Field Programmable Gate Array, FPGA) was used in this study to simplify the circuit design of the Braille display. With the use of the hardware description language, the Braille display control system composed of a microcontroller, logic gates, and other circuits was designed and integrated into the FPGA chip. This single chip can then be used to replace the entire circuit board to control the Braille display. FPGA provides a convenient mechanism to allow implement hardware, making the overall circuit design more flexible.
During the early phase of the study, a FPGA development kit, combined with an eight slots main circuit board and eight Braille cells, served as a platform for developing the Braille display control system. After completing the design of the 8051 microprocessor core, logic modules, and other circuits, the control system successfully achieved was then loaded onto a development module. By integrating the development module, the main circuit board, and the Braille cells, the prototype of a FPGA based Braille display was accomplished.
The information signals at the computer side were sent through the USB interface to the 8051 microprocessor core inside the Braille display FPGA chip, which were then converted into Braille messages. Then, parallel outputs was carried out through the logic control module made up of 3 to 8 decoder and data latch modulus to send signals to the specified Braille cells. The functional test results show that the overall system design of the FPGA based Braille display is appropriate. The design goals of hardware simplification, user-friendly operation, and maintenance convenience are all achieved.