APPARATUS AND METHOD FOR INTERFACING USB USING DMAC

摘要

PURPOSE: An apparatus and method for interfacing a USB using a DMAC(direct memory access controller) is provided to promote a transmission speed of data by reducing a load of a CPU in case that serial data are transmitted, and by interfacing the serial data with a DMAC. CONSTITUTION: A ROM(23) stores device descriptor contents defined from a USB spec. A USB(Universal Serial Bus) signal processing unit(25) converts serial data transmitted from an external USB host(28) into determined byte data. The USB signal processing unit(25) converts the determined byte data into serial data for applying the data to a USB protocol. A DMAC interface unit(21) checks a storing state of data of a transmission buffer(22) and generates DMAC request signals according to the storing state. A DMAC(20) controls a transmission or a receipt of data according to the DMAC request signals of the DMAC interface unit(21). A processor(26) sets the DMAC(20) and the DMAC interface unit(21) as a transmission mode in case that the data are transmitted. A CPU interface unit(27) provides an interface of the processor(26) and the DMAC interface unit(21). The transmission buffer(22) temporarily stores data stored in an arbitrary memory according to a determined control signal of the DMAC(20) in case that the data are transmitted.