Patent ID: 7340541

Claim:
An apparatus for changing the direction of a data flow when buffering bidirectional digital input/output (I/O) lines, the apparatus comprising: a first integrated circuit (IC) coupled to a first bidirectional digital I/O line, the first IC comprising: a first bidirectional buffer coupled to the first bidirectional digital I/O line, a second bidirectional buffer coupled to the first bidirectional buffer, and a first control unit operable to control the driving direction of each of the first and second bidirectional buffers independently to change the direction of the data flow from a first direction to a second direction; and a second IC coupled to the first IC, the second IC comprising: a third bidirectional buffer coupled to the second bidirectional buffer of the first IC, and a second control unit operable to control the driving direction of the third bidirectional buffer to change the direction of the data flow from the first direction to the second direction; wherein the data flow in the first direction corresponds to data being sent from the first IC to the second IC, and wherein the data flow in the second direction corresponds to data being sent from the second IC to the first IC; wherein, in changing the direction of the data flow from the first direction to the second direction, the first control unit is operable to change the driving direction of the second bidirectional buffer to the second direction during a first clock cycle, the second control unit is operable to change the driving direction of the third bidirectional buffer to the second direction during a second clock cycle, and the first control unit is operable to change the driving direction of the first bidirectional buffer to the second direction during a third clock cycle.