IDELAYE3 Attributes - IDELAYE3 Attributes - UG861

Spartan UltraScale+ FPGAs SelectIO Resources User Guide (UG861)

Document_ID
UG861
Release_Date
2026-04-28
Revision
1.1 English

The following table lists the IDELAYE3 attributes.

Table 1. IDELAYE3 Attributes
Attribute Possible Values Default Type Description
DELAY_SRC DATAIN IDATAIN IDATAIN String For more information, see DELAY_SRC Attribute.
CASCADE

NONE

MASTER

SLAVE_MIDDLE

SLAVE_END

NONE String For more information, see CASCADE Attribute.
DELAY_TYPE

FIXED VAR_LOAD

VARIABLE

FIXED String

The DELAY_TYPE attribute sets the type of delay used. It can be FIXED,

VARIABLE or VAR_LOAD. See DELAY_TYPE Attribute for further information.

DELAY_VALUE

0–1100 (TIME)

0–511 (COUNT)

0 Decimal

Spartan UltraScale+ devices support up to 1.1 ns.

COUNT mode: Desired value in taps.

REFCLK_FREQUENCY

300.00–800.00

( IDELAYCTRL)

300.00–2666.67

BITSLICE_CONTROL)

300.0 1 significant digit float

The REFCLK_FREQUENCY attribute specifies the reference clock of the IDELAYCTRL frequency in MHz.

This attribute must mimic the clock frequency applied at the IDELAYCTRL component, except when DELAY_FORMAT is set to COUNT (when the attribute can be left at the default value).

DELAY_FORMAT TIME COUNT TIME String

When set to TIME, the delay equals the value given in DELAY_VALUE (specified in ps) plus an Align_Delay. Calibrated using the REFCLK_FREQUENCY set here applied at the IDELAYCTRL component.

When set to COUNT, the initial tap setting goes to whatever number of taps is specified in DELAY_VALUE.

This does not give a constant delay because the tap delays vary with PVT.

For more information, see DELAY_FORMAT Attribute.

UPDATE_MODE

ASYNC

SYNC

MANUAL

ASYNC String For more information, see UPDATE_MODE Attribute.
SIM_DEVICE ULTRASCALE_PLUS ULTRASCALE String

Sets the device version

(ULTRASCALE_PLUS)

  1. When in TIME mode, calibration affects the availability of bit slices within the nibble. See HP I/O Bank Overview for more information.