Datasheet
SCBA015A
7–22
Fast GTLP Backplanes With the GTLPH1655
Features of the SN74GTLPH1655
Functional Description: SN74GTLPH1655 – UBT
The SN74GTLPH1655 is described as a UBT, i.e., a bus driver for a wide variety of applications.
The function of this component can be controlled and changed in accordance with the signals
and static voltage levels applied to the various control inputs.
By means of the control inputs OE, OEAB
, OEBA, LEAB, and LEBA, one of the following three
operating modes for the SN74GTLPH1655 can be selected:
• Transparent mode
The SN74GTLPH1655 behaves like a bidirectional bus driver, for example, the ’245.
• Level-sensitive storage (latch) mode
The SN74GTLPH1655 behaves like a level-sensitive register (latch), for example, a ’373.
However, in this case, it can be used bidirectionally.
• Edge-triggered storage (flip-flop) mode
The circuit behaves like an edge-triggered register, for example, a ’374. In this mode, it can
be used bidirectionally.
The operating mode can be set separately for each direction of transmission. An example of a
typical application is shown in Figure 12.
CPU Board
I/O System
UBT
UBT
Cache
Bus
Control
CPU
Figure 12. Typical Bus Application for a UBT