An embedded single-board computer (SBC) system based on AT91RM9200 was designed for monitoring and controlling the digital beam position monitor system of Shanghai Synchrotron Radiation Facility (SSRF) through the Virtex-4 FPGA in the digital processing board. The SBC transfers the configuration commands from the remote EPICS to the FPGA, and calculates the beam position data. The interface between the FPGA and the SBC is the Static Memory Controller (SMC) with a peak transfer speed of up to 349 Mbps. The 100 Mb Ethernet is used for data transfer between the EPICS and SBC board, and a serial port serves as monitoring the status of the embedded system. Test results indicate that the SBC board functions well.