IOBUFDS_DCIEN

UltraScale Architecture SelectIO Resources User Guide (UG571)

Document ID
UG571
Release Date
2022-08-31
Revision
1.14 English

The IOBUFDS_DCIEN primitive shown in This Figure is available in the HP I/O banks. It has an IBUFDISABLE port that can be used to disable the input buffer during periods that the buffer is not being used. The USE_IBUFDISABLE attribute must be set to TRUE, the IBUFDISABLE port must be controlled, and SIM_DEVICE set to ULTRASCALE for this primitive to have the expected behavior that is specific to the UltraScale architecture. The IOBUFDS_DCIEN primitive also has a DCITERMDISABLE port that can be used to manually disable the optional on-die receiver termination features (uncalibrated or DCI). See DCI—Only Available in the HP I/O Banks and Uncalibrated Input Termination in I/O Banks for more details.

Figure 1-35:      Differential Bidirectional Buffer with Input Buffer Disable and On-Die Input Termination Disable (IOBUFDS_DCIEN)

X-Ref Target - Figure 1-35

X16095-diff-bidi-buffer-w-input-buffer-disable-and-on-die-input-term-disable-iobufds_dcien.jpg

The IOBUFDS_DCIEN primitive can disable the input buffer and force the O output to the internal logic to a logic-Low when the IBUFDISABLE signal is asserted High and the output buffer is 3-stated (T = High). If the I/O is using an on-die receiver termination feature (uncalibrated or DCI), this primitive disables the termination legs whenever the DCITERMDISABLE signal is asserted High and the output buffer is 3-stated (T = High).

When the output buffer is 3-stated (T = High), the input buffer and any on-die receiver termination (uncalibrated or DCI) are controlled by IBUFDISABLE and DCITERMDISABLE, respectively. When the output buffer is not 3-stated (T = Low), the input buffer and any on-die receiver termination (uncalibrated or DCI) are disabled and force the O output (to the internal logic) to a logic-Low. These features can be combined to reduce power whenever the input is idle for a period of time.

Although uncommon, if a design requires an input be constantly enabled while maintaining the ability to dynamically control DCI, this primitive can be used by floating the IBUFDISABLE pin and setting the USE_IBUFDISABLE attribute to FALSE.