Memory access apparatus
View Patent ↗A memory access apparatus is provided with a processor, an interface (I/F) circuit, and a memory control circuit. The processor is provided with an access-request generating circuit which issues a memory access request. The I/F circuit is provided with a flip-flop (F/F) circuit which holds the memory access request outputted from the processor in response to a clock signal. The memory control circuit is provided with an access processing circuit which executes an access process that complies with the memory access request held by the F/F circuit.
1. A memory access apparatus comprising:
a processor; an interface; and
a memory control circuit;
an interface external to said processor and said memory control circuit; and
a clock generator providing a clock signal common to said processor, said interface, and said memory control circuit for timing control, wherein
said processor comprises an issuer which issues a memory access request, said memory access request being a memory read or write request,
said interface comprises a first holder which holds the memory access request issued by said issuer processor in response to the clock signal,
said memory control circuit comprises an access processor processing circuit which executes an access process in accordance that complies with the memory access request held by said first holder, and wherein
said memory control circuit further comprises a first outputter which outputs a first ready/busy signal to said interface, the first ready/busy signal indicating whether said access processing circuit is ready to execute the memory access request by referring to a process state of said access processor,
said interface further comprises a creator which creates a response signal to said processor based on the memory access request issued by said processor issuer and the first ready/busy signal outputted by said first outputter, and
said processor further comprises a second outputter which outputs a second ready/busy signal to said interface based on the response signal created by said creator, the second ready/busy signal indicating acknowledgment by said processor for said memory control circuit to proceed with execution of the memory access request.
2. A memory access apparatus according to claim 1 , wherein said interface further comprises a second holder which holds the second ready/busy signal outputted by said second outputter in response to the clock signal, and said access processing circuit processor executes the access process by referring to the second ready/busy signal held by said second holder.
3. A memory access apparatus according to claim 1 , wherein said creator includes a first signal creator which creates a state identifying signal which identifies a state of the memory access request held by said first holder and a second signal creator which creates the response signal by performing an AND operation on the state identifying signal created by said first signal creator and the first ready/busy signal outputted by said first outputter.
4. A memory access apparatus according to claim 3 , wherein said memory access request includes word count information in which a word count of access data is written, and the said first signal creator creates the state identifying signal different depending on the word count information.