System on a chip having system bus external bus and bus arbiter with programmable priorities for both buses article and method for assigning programmable priorities

摘要

PURPOSE: A SOC(System On a Chip) is provided to include a multi-managing bus arbiter for increasing efficiency of a system bus and an external bus. CONSTITUTION: An external bus(415) connects inner of a semiconductor chip with ROM(482), DRAM(484), external input/output device(474), and external device(473). A system bus(410) is AMBA(Advanced Micro-controller Bus Architecture). DDMA blocks(424-426) are connected with corresponding IP blocks. An inner memory controller(462) accesses inner memory. An external memory controller(440) connects the system bus(410) and the external bus(415). A DRAM refresh controller generates a signal, which controls the refresh of the external DRAM(484).