Abstract: An SPI master interface with AMBA AXI 3.0 interface is designed for PKU-DSPⅡ single chip, which supports four transfer modes, variable frame length, frequency programmable clock output and five interrupt types.Simultaneously, the bootrom program for the RISC DSP is also proposed, providing normal booting from external FLASH and system updating of the boot-loader codes in the external FLASH.Both the function simulation and FPGA prototyping show that PKU-DSPⅡ can boot and conduct system updating through the external FLASH successfully, which provides good evidence for the correctness of the design of the SPI master interface and the bootrom program.The design has been implemented with CSMC 0.18μm CMOS technology for taping out.