A High Speed DMA Transaction Method for PCI Express Devices

A novel PCI Express (peripheral component interconnection express) direct memory access (DMA) transaction method using bridge chip PEX 8311 is proposed. Furthermore, a new method on optimizing PCI Express DMA transaction through improving both bus-efficiency and DMA-efficiency is presented. A finite state machine (FSM) responding for data and address cycles on PCI Express bus is introduced, and a continuous data burst is realized, which greatly promote bus-efficiency. In software design, a driver framework based on Windows driver model (WDM) and three DMA optimizing options for the proposed PCI Express interface are presented to improve DMA-efficieney. Experiments show that both read and write hardware transaction speed in this paper exceed PCI theoretical maximum speed (133 Mbytes/s).