| 摘要 |
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of data to the receiving data processing system in conjunction with an indication that the first packet of data is no longer valid to read.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.
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