Design of SDLC communication module based windows CE

SDLC bus communication module was designed and implemented in this paper. AM85C30 is used to accomplish the SDLC protocol control and adapts to PC/104 bus. Driver software is designed based on DMA streams driver under Windows CE 5.0. In order to achieve the maximum baud rate and lowering down the CPU usage, data exchange between AM85C30 and the host is implemented using DMA. Software circular FIFO is designed for buffering the SDLC frame data and status information, solving the frame losing problem when transferring data in high speed. RS485 bus is used in physical layer and works in half-duplex mode. The network topology is simplified and communication reliability is enhanced. The SDLC module is deployed in a launch vehicle video acquisition system. Field working indicates that the system can achieve stable speed of 2Mbps for both channels simultaneously. (2013) Trans Tech Publications, Switzerland.