The Improvement And Optimization Of LED Screen Controller Based On USB

In recent years, LED display market has been the rapid development, and LED display has been widely applied in various fields. For the emerging market of small-screen LED lighting, our embedded system propose research design the LED screen controller based on USB. The controller can be on the LED screen in real-time lighting control and user control of DIY. At present there is no related products for the domestic market. On the basis of the first stage research task of the LED screen controller based on USB, this paper improves and optimizes the perfect the function of the LED screen controller.In this paper, we give a detailed analysis of the system LED screen controller and its working principle, Including analysis of the overall design; choice of related devices ; system hardware design; module design of the structure and procedures.This article improves the way of the USB synchronization transmission. Through analyzing the I/O transmission control methods, we change the original programmable I/O addressing to the direct memory access (DMA) mode. Through the DMA engine of LPC1248, we achieve USB data transmission. And we make C programme to join the interruption of DMA mode. The USB transmission improved ways include perfecting the synchronization mode function, improving the operating efficiency of the LPC2148, raising the USB transmission speed on synchronization mode.This article improves USB functions on its storage mode. Firstly we introduce the norms of USB agreement; secondly we analyse the operation process of USB Bulk-Only; thirdly we configurate LED screen controller descriptorsin in accordance with the Bulk-Only mode; last we response the relevant instructions of SCSI command sets. In storage mode, PC enumerates USB controller based on the LED screen as a mass storage class (MSC). Not only improving the storage function, but also making the LED screen controller operation more convenient.This article applies and improves the FAT file system method on the NAND FLASH. We make analysis on a variety of document management system; choose the most suitable FAT16 file system; manage the NAND FLASH of the LED screen controllers. For the characteristics of v and the lack of the general FAT16 file system, we improve the storage mode of the FAT table and FDT form, and introduce the block balance loss and the waste recycling strategy, so that the FAT16 file system reliability is improved.This article optimizes the system code and improves the system operating efficiency. At the same time, we curing the code into the FLASH in chip, so that the LED screen controller based on USB can run off-line. The test of USB functions showed that: data communications is smooth on synchronous mode, and stable and reliable on storage mode.This design has been fully verified. In the full machine course testing, the system is running stability, excellent performance, while system functions are easy to expand and maintain.