Apparatus for processing digital signals

摘要

The apparatus contains a microprocessor circuit, which comprises a preprocessor which is not DMA-capable in itself and a DMA-capable central processor. Both processors can be made to communicate with each other by means of a main memory. This is performed by temporarily cutting off the communication path between said DMA-capable central processor and said main memory, specifically by an artificial DMA request via the address line of said preprocessor, and by establishing instead a communication path between said preprocessor and said main memory. The communication of said preprocessor with said main memory is started after said central processor has sent a return message signal to said preprocessor, whereby it confirms that its own communication with said main memory is completed.