Abstract: A microcontroller includes an external interface terminal group, a data transmit/receive section, and a DMA controller comprised of an address register for storing therein an address of a hardware serving as an object to be accessed by DMA, registers for executing read/write by the DMA, a control flag for controlling the start of the DMA, and a timing controller of the DMA. The microcontroller further includes a register for storing therein flag information for determining whether access can be executed or not by the DMA and a unit for outputting a bus state recognition signal indicating whether a bus state is rendered in a state to be accessed or not by the DMA.

Abstract: A microcontroller 100 comprises an external interface terminal group 102 for executing transmission and reception of data relative to an outside, a data transmit/receive section 104, and a DMA controller 110 comprised of an address register 112 for storing therein an address of a hard ware serving as an object to be accessed by DMA, registers (113, 114) for executing read/write by the DMA, a control flag 111 for controlling the start of the DMA, and a timing controller 116 of the DMA.