Universal protocol data receiver

• US 4,852,127 A
• Filed: 03/22/1985
• Issued: 07/25/1989
• Est. Priority Date: 03/22/1985
• Status: Expired due to Term

• Current Assignee: Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Original Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Inventors: Riddle, Guy G., Marshall, William T., Fraser, Alexander G.
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Chin, Stephen
• Application Number:
  US06/714,834
• Time in Patent Office: 1,586 Days
• Field of Search: 375/7, 375/37, 375/108, 375/99, 375/94, 340/825.54, 371/53, 371/34, 371/38, 371/39, 179/18 ES, 365/190, 365/191, 365/195, 370/80, 370/84, 370/108
• US Class Current: 375/340
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 1/0091 arrangements specific to receivers, e.g. format detection detection of data rate H04L25/0262; detection of coding rate H04L1/0046
• CPC Class Codes: H04L 1/1835 Buffer management
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/9052 with buffers of different sizes

Abstract

A universal protocol data receiver is disclosed which is capable of receiving data streams in character mode and block mode, providing flow control and error detection and correction. The receiver is divided into two stages separated by a first-in, first-out buffer register. The first stage handles flow control and error processing as well as initialization. The second stage handles interfacing with the data utilizing mechanism and flow control acknowledgements. The FIFO buffer is divided into two parts by a movable barrier which limits the access of the second stage. The barrier permits error processing by hiding incoming blocks of data behind the barrier until processing is complete. Both a hardware and a software implementation of the receiver are disclosed.

Claims

1. A data receiver including:

a first-in, first-out buffer storage means,

a movable barrier in said storage means for dividing said storage means into two parts,

means for storing received data in one of said parts beginning at a storage location adjacent to said barrier and ending at an end location away from said barrier,

means for processing said received data in said one part,

means for moving said barrier to said end location after processing by said processing means, and

means for limiting access to the other of said two parts.

2. The data receiver according to claim 1 further comprising:

means for inserting data into said buffer storage means behind said barrier as said data is received.

means for checking said data, and

means for moving said barrier behind said data following the successful operation of said check means.

3. The data receiver according to claim 2 further comprising:

means for removing data from said storage means only ahead of said barrier.

4. A method of receiving a digital data stream from a remote transmitter comprising the steps of

passing said data through a first receiving stage for processing command codes interspersed in said data stream,

storing said data in a first-in, first-out storage buffer under the control of said command codes,

error-processing data stored in said storage buffer,

removing said data from said storage buffer by a second receiving stage,

passing said data on to a data utilization device, and

maintaining a moveable barrier within said storage buffer for rendering a portion of said storage buffer not processed by said error-processing step unavailable to said second receiving stage.

5. The method of receiving a digital data stream according to claim 4 further comprising the steps of

generating a response to certain of said command codes in a character mode data stream which responses can be used at a remote transmitter to implement flow control operations.

6. The method of receiving a digital data stream according to claim 4 further comprising the steps of

identifying unique trailer blocks of data in said data stream, and

generating reply codes in response to the processing of said trailer blocks.

7. The method of receiving a digital data stream according to claim 6 further comprising the steps of

disassembling said trailer block into a beginning-of-trailer code, a length code and a sequence number code.

8. The method of receiving a digital data stream according to claim 7 further comprising the steps of

detecting and correction errors in said data stream in response to said disassembled trailer block.

9. A method for processing data in a receiver including a first-in, first-out buffer storage means and a movable barrier in said storage means for dividing said storage means into two parts, comprising:

a step of storing received data in one of said parts beginning at a storage location adjacent to said barrier and ending at an end location away from said barrier,

a step of processing said received data in said one part,

a step of moving said barrier to said end location after processing by said processing means, and

a step of limiting access to the other of said two parts.