Framing codes for high-speed parallel data buses

• US 6,275,880 B1
• Filed: 02/22/1999
• Issued: 08/14/2001
• Est. Priority Date: 10/22/1998
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Company (HP Inc.)
• Original Assignee: 3Com Technologies Ltd (HP Inc.)
• Inventors: Fanning, Neil O., Butler, J. Noel, Hughes, Mark A., Cremin, Con, Quinlan, Una, OʼNeill, Eugene
• Primary Examiner(s): Dharia, Rupal
• Application Number:
  US09/253,537
• Time in Patent Office: 904 Days
• Field of Search: 710/100, 707/100, 707/101, 707/102, 707/103, 707/104, 341/50, 341/55, 341/67, 341/106
• US Class Current: 710/100
• CPC Class Codes: H04L 1/0063 Single parity check
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure

Abstract

A plurality of serial data streams are transmitted on a corresponding plurality of lines at a common frequency in equal groups of symbols. A framing signal composed of groups of symbols corresponding in number to groups of data symbols is transmitted on an additional control line. Each group of symbols in the framing signal includes a majority of symbols capable of representing a first plurality of code words and a second plurality, substantially less than the first plurality, of valid code words, and a minority of symbols which constitute parity check symbols. Each of the valid code words consists of a first sub-group of similar symbols and a second plurality of similar symbols. For some of the valid code words the symbols in the first sub-group are similar to the symbols in the second sub-group. For other valid code words the symbols in the first sub-group are different from the symbols in the second sub-group. The valid code words correspond to groups which represent (a) start of a data packet or block; (b) data/(c) a gap between groups of data; and (d) an idle state. The sequence of groups in the framing signal is monitored by means of a state machine.

Claims

1. A method of transmitting data comprising:

transmitting a plurality of serial data streams on a corresponding plurality of lines at a common frequency, said data being transmitted in equal groups of symbols;

transmitting on an additional line a framing signal composed of groups of symbols corresponding in number to groups of data symbols;

wherein each group of symbols in the framing signal comprises a majority of symbols capable of representing a first plurality of code words and a second plurality, substantially less than the first plurality, of valid code words, and a minority of symbols which constitute parity check symbols.

5. A method according to claim 1, each of said valid code words comprising a first sub-group of similar symbols and a second plurality of similar symbols, wherein for some of said valid code words the symbols in the first sub-group are similar to the symbols in the second sub-group and for other valid code words the symbols in the first sub-group are different from the symbols in the second sub-group.

6. A method according to claim 1, wherein said plurality of lines comprise a plurality of parallel lines to constitute a parallel bus.

2. A method of transmitting data comprising:

transmitting a plurality of serial data streams on a corresponding plurality of lines at a common frequency, said data being transmitted in equal groups of symbols; and

transmitting on an additional line a framing signal composed of groups of symbols corresponding in number to groups of data symbols;

wherein each group of symbols in the framing signal comprises a majority of symbols capable of representing a first plurality of code words and a second plurality, substantially less than the first plurality, of valid code words, and a minority of symbols which constitute parity check symbols; and

each of said valid code words consists of a first sub-group of similar symbols and a second plurality of similar symbols, wherein for some of said valid code words the symbols in the first sub-group are similar to the symbols in the second sub-group and for other valid code words the symbols in the first sub-group are different from the symbols in the second sub-group.

3. A method according to claim 2, wherein said valid code words correspond to groups which represent (a) start of a data packet or block;

(b) data;

(c) a gap between groups of data; and

(d) an idle state.

4. A method of transmitting data comprising:

transmitting a plurality of serial data streams on a corresponding plurality of lines at a common frequency, said data being transmitted in equal groups of symbols; and

transmitting on an additional line a framing signal composed of groups of symbols corresponding in number to groups of data symbols;

wherein each group of symbols in the framing signal comprises a majority of symbols capable of representing a first plurality of code words and a second plurality, substantially less than the first plurality, of valid code words, and a minority of symbols which constitute parity check symbols; and

said method further comprising monitoring a sequence of groups in the framing signal by means of a state machine according to at least one valid sequence, and detecting errors when the state machine detects an illegal sequence.

7. A method of transmitting data comprising:

transmitting a plurality of serial data streams on a corresponding plurality of lines at a common frequency, said data being transmitted in equal groups of symbols; and

transmitting on an additional line a framing signal composed of groups of symbols corresponding in number to groups of data symbols;

wherein each group of symbols in the framing signal comprises a majority of symbols capable of representing a first plurality of code words and a second plurality of valid code words, and a minority of symbols which constitute parity check symbols.