Research On Embedded LED Control System Based On The Synchronous DMX512 Protocol

With the development of micro electronic technology, automation technique, and computer technique, as well as the maturity and perfection of semiconductor manufacturing technology and craft make the brightness and lifetime of LED advance and develop rapidly. Meanwhile, the increasing perfection of full-color LED display technique makes the application prospect of LED more expansive, especially in the application of LED lighting on stage. Control system is the key part of LED lighting system. In order to satisfy the demand of current LED, namely high capacity of lantern controlled, high control rate, and diverse occasions applied, the thesis designs embedded LED control system based on synchronous DMX512 protocol.The thesis researches on common lighting control protocol. Asynchronous DMX512 data communication protocol is applied massively in domestic and foreign stage lighting control system, which has the defects including slow transmission rate and small capacity of lantern, etc. Aiming at this, the thesis puts forward to apply synchronous DMX512 protocol to LED control system in order to satisfy the demand of current stage control field. In addition, according to the characteristics of LED, including diverse occasions of application and high-level demand of the real-time, convenience, and rapidity of the control, the thesis applies dual-mode USB interface technique to LED control system.The thesis completes the design of software and hardware of bottom layer and VB upper-computer software of the control system. The hardware adopts STC11F series MCU as the major controller, which is to control synchronous DMX512 control chip and USB interface chip. It adopts TM1803 as the synchronous DMX512 control chip and CH375 as USB interface ship. For the software, it primarily completes gray level control of singlet line cascading of LED. File enumeration and file read are completed in the USB host model, and single chip receives document of PC through USB communication in the USB salve model. Upper-computer software major achieves USB communication and preprocessing BMP file. Through USB interface, the processed BMP file will be sent to MCU. MCU will receive process BMP file through dual-model USB communication, which will be showed on the LED screen with dynamic and static status display in order to achieve gorgeous stage effect.The application of synchronous DMX512 protocol improves and advances control capacity and control rate of control system greatly. Meanwhile, the thesis applies dual-model USB interface technology to LED control system, there's certain innovation of the control technique. Experiments show that the design can achieve mild control of LED gray level and the stable communication of dual-model USB interface, the hardware and software can run stablely and reliabely.