Interface for connecting a bus to a random access memory using a two wire link

• US 5,724,537 A
• Filed: 03/06/1997
• Issued: 03/03/1998
• Est. Priority Date: 03/24/1994
• Status: Expired due to Term

• Current Assignee: Coases Investments Bros LLC (Intellectual Ventures LLC)
• Original Assignee: Discovision Associates (Pioneer Corporation)
• Inventors: Jones, Anthony Mark
• Primary Examiner(s): Lane, Jack A.
• Assistant Examiner(s): Verbrugge, Kevin
• Application Number:
  US08/812,820
• Time in Patent Office: 362 Days
• Field of Search: 395/401, 395/446, 395/398, 395/509, 395/309, 345/200
• US Class Current: 711/1
• CPC Class Codes: G06F 12/0207 with multidimensional access, e.g. row/column, matrix
• CPC Class Codes: G06F 12/04 Addressing variable-length words or parts of words
• CPC Class Codes: G06F 12/0607 Interleaved addressing
• CPC Class Codes: G06F 13/16 for access to memory bus G06F13/28 takes precedence
• CPC Class Codes: G06F 13/28 using burst mode transfer, e.g. direct memory access DMA, cycle steal G06F13/32 takes precedence
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/423 characterised by memory arrangements H04N19/433 takes precedence
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding

Abstract

The invention provides a RAM interface for connecting a bus to RAM wherein a separate address generator generates the addresses the RAM interface needs to address the RAM. The interface utilizes a plurality of swing buffers, and has a control module for coordinating accesses thereto, which is connected to the address generator by a specialized two-wire interface. The address generator and the source of data are clocked asynchronously and at different clock rates.

Claims

1. An apparatus for connecting a bus to a RAM comprising:

a single address generator providing complete addresses that is clocked at a first clock rate;

a RAM interface, comprising;

a plurality of swing buffers connected to a bus for receiving therefrom a plurality of data words from a source at a second clock rate;

a control coupled to said swing buffers;

a two-wire link connecting said control with said address generator wherein a request/acknowledge protocol is implemented therebetween via said link, wherein said two-wire link comprises;

a sender, a receiver, and a clock connected to said sender and said receiver, wherein data is transferred from said sender to said receiver upon a transition of said clock only when said sender is ready and said receiver is ready;

wherein the interface is clocked at a third clock rate that is asynchronous with said first clock rate and said second clock rate, and data is transferred between a selected swing buffer and a RAM in response to a first signal that is generated by said control when said control receives an address from the address generator and said control receives a second signal from said selected swing buffer via said communication link.

2. The apparatus according to claim 1, wherein said address generator generates a block address for said selected swing buffer, and a row address for said RAM, wherein the data is transferred between said selected swing buffer and a row of said RAM according to said row address.

3. The apparatus according to claim 2, wherein column addresses of said RAM are generated by said control.

4. The apparatus according to claim 1, further comprising a two-wire interface in said bus between said control and said source of said data words.

5. The apparatus according to claim 1, wherein said address generator is responsive to control tokens in said data words.

6. The apparatus according to claim 2, wherein said address generator is responsive to selected bits of said data words.