Data processing device with direct memory access function

Abstract

Abstract In this data processing device, a request for direct memory-access operation is detected as one of interrupt signals. When such an interrupt is detected, a interrupt controller (10) generates a vector corresponding to the interrupt signal. On the basis of this vector, a DMA controller (20) generates a control signal showing whether the interrupt signal is a normal interrupt or an interrupt for requesting the direct memory-access operation. A CPU (30) includes a ROM (34) for storing the control function for achieving the direct memory-access operation, as micro-codes. When the DMA controller (20) generates a control signal corresponding to the interrupt signal, the CPU (30) sequentially reads out the micro-codes, to execute the direct memory-access operation. Specifically, if an interrupt for requesting the direct memory-access operation is detected, a processing space, different from that used for a normal interrupt processing, is used. The processing area has a prestorage of the data . corresponding to the data stored in various types of registers provided in the conventional DMA controller. By using this data, the data transfer is controlled by the micro-codes.

Inventors

• 👤 Ziro C/O Patent Division Hirahara
• 👤 Akihito C/O Patent Division Abe

Bibliographic Details