Method and apparatus for dynamic signal modification on a parallel bus

• Main Authors: LEE FEE, CHILDS KEITH
• Format: Patent
• Language: English
• Published: 13.11.2001
• Edition: 7
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PULSE TECHNIQUE; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

A SCSI bus expander provides signal conditioning for transmitted data pulses that is particular to a negotiated data transfer rate. The expander monitors the bus arbitration to determine the devices involved in the transfer, and thereafter monitors the data transfer rate negotiations to determine the transfer rate to be used by that particular combination of devices. An indication of the transfer rate is stored in a memory device at an address determined by the device IDs. The transfer rate is then used to select tap values for tap lines that modify the pulse width and/or a propagation delay of the pulse, so as to correct for signal degradation and to align it better relative to other signals during data transmission. The specific tap values may vary for the different combinations of transmitting and receiving devices involved in the transfer, since the manner in which the pulse characteristics should be modified may be different for different transmission rates.