Method and system of bi-directional parallel port data transfer between data processing systems
First Claim
1. A method of bi-directional data transfer via an electrical connection coupled between a standard parallel port of a first data processing system and a standard parallel port of a second data processing system, said method comprising the steps of:
- signaling said first data processing system that said second data processing system is ready to receive data;
transmitting a first packet of data to said second data processing system in conjunction with an indication that said first packet of data is valid to read;
reading said first packet of data utilizing said second data processing system;
transmitting an acknowledgment signal to said first data processing system indicating that said second data processing system has received said first packet of data;
in response to said acknowledgment signal, transmitting a subsequent packet of data to said second data processing system in conjunction with an indication that said first packet of data is no longer valid to read, wherein said subsequent packet of data and said indication that said first packet of data is no longer valid to read are output by said first data processing system in a single write operation; and
thereafter, transmitting to said second data processing system an indication that said subsequent packet of data is valid to read.
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Abstract
A method and system are described for bi-directional data transfer between a parallel port of a first (sending) data processing system and a parallel port of a second (receiving) data processing system. The process begins by signaling the sending data processing system that the receiving data processing system is ready to receive data. The sending data processing system then transmits a first packet of data to the receiving data processing system in conjunction with an indication that the first packet of data is valid to read. After reading the first packet of data, the receiving data processing system acknowledges receipt of the first packet of data by transmitting a signal to the sending data processing system. In response to the acknowledgment signal, the sending data processing system transmits a subsequent packet of data to the receiving data processing system in conjunction with an indication that the first packet of data is no longer valid to read. By transmitting the subsequent packet of data and the data invalid signal in a single output operation to the parallel port, the present invention increases the throughput of the data transfer while maintaining data integrity.
118 Citations
9 Claims
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1. A method of bi-directional data transfer via an electrical connection coupled between a standard parallel port of a first data processing system and a standard parallel port of a second data processing system, said method comprising the steps of:
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signaling said first data processing system that said second data processing system is ready to receive data; transmitting a first packet of data to said second data processing system in conjunction with an indication that said first packet of data is valid to read; reading said first packet of data utilizing said second data processing system; transmitting an acknowledgment signal to said first data processing system indicating that said second data processing system has received said first packet of data; in response to said acknowledgment signal, transmitting a subsequent packet of data to said second data processing system in conjunction with an indication that said first packet of data is no longer valid to read, wherein said subsequent packet of data and said indication that said first packet of data is no longer valid to read are output by said first data processing system in a single write operation; and thereafter, transmitting to said second data processing system an indication that said subsequent packet of data is valid to read. - View Dependent Claims (2, 3)
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4. A system for bi-directional data transfer, comprising:
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a first and a second data processing system; an electrical connection coupled between a standard parallel port of said first data processing system and a standard parallel port of said second data processing system; means for signaling said first data processing system that said second data processing system is ready to receive data; means for transmitting a first packet of data to said second data processing system in conjunction with an indication that said first packet of data is valid to read; means for reading said first packet of data utilizing said second data processing system; means for transmitting an acknowledgment signal to said first data processing system indicating that said second data processing system has received said first packet of data; means, responsive to said acknowledgment signal, for transmitting a subsequent packet of data to said second data processing system in conjunction with an indication that said first packet of data is no longer valid to read, wherein said subsequent packet of data and said indication that said first packet of data is no longer valid to read are output by said first data processing system in a single write operation; and means for thereafter transmitting to said second data processing system an indication that said subsequent packet of data is valid to read. - View Dependent Claims (5, 6, 7, 8, 9)
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Specification