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Method for data communication

DC
  • US 5,398,326 A
  • Filed: 02/19/1993
  • Issued: 03/14/1995
  • Est. Priority Date: 05/15/1989
  • Status: Expired due to Term
First Claim
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1. A method for data communication by serial block transfers of data on a data line between a first system and at least one second system, said serial block transfers of data having at least one data bit and said data line having at least one voltage state, comprising the steps of:

  • (a) defining a current operating mode to be either a write mode or a read mode, so that said at least one data bit of said serial block transfers of data is transferred from said first system to said at least one second system when said current operating mode is said write mode and said at least one data bit of said serial block transfers of data is transferred from said at least one second system to said first system when said current operating mode is said read mode;

    (b) driving said data line toward a first voltage level by said first system and thereafter driving said data line to make a transition of said data line toward a second voltage;

    (c) detecting said transition of said data line toward said second voltage level by said at least one second system;

    (d) and when said current operating mode is said read mode,(d1) driving said data line toward said second voltage level by said at least one second system and holding said data line at said second voltage level for a first time duration, said first time duration having a first length, said first length dependent upon said at least one data bit of said serial block transfers of data and releasing said data line after said first time duration, and(d2) testing the at least one voltage state of said data line by said first system within a time window, said time window terminates before a minimum possible duration of said first time duration;

    (e) and when said current operating mode is said write mode,(e1) driving said data line toward a data voltage level dependent upon said at least one data bit of said serial block transfers of data said data voltage level approximately equal to said first voltage level or said second voltage level;

    (e2) waiting for a second time duration, said second time duration having a second length, said second length dependent upon said at least one data bit of said serial block transfers of data and then testing the at least one voltage state of said data line to ascertain the at least one data bit of said serial block transfers of data written; and

    (e3) in said first system, holding said data line to said data voltage level over said time window which begins before an earliest possible expiration, for said at least one second system of said second time duration, and which ends after a latest possible expiration, of said second time duration.

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