RPM_GRID - 2023.2 English

Vivado Design Suite Properties Reference Guide (UG912)

Document ID
Release Date
2023.2 English

The RPM_GRID property defines the RLOC grids as absolute coordinates instead of relative coordinates. The RPM_GRID system is used for heterogeneous RPMs where the cells belong to different site types (such as a combination of SLICEs, block RAM, and DSP). Because the cells can occupy sites of various sizes, the RPM_GRID system uses absolute RPM_GRID coordinates that are derived directly from the target device.

The RPM_GRID values are visible in the Site Properties window of the Vivado Integrated Design Environment (IDE) when a specific site is selected in the Device window. The coordinates can also be queried with Tcl commands using the RPM_X and RPM_Y site properties. For more information on using the RPM_GRID property, and defining RPMs with absolute coordinates, refer to the Vivado Design Suite User Guide: Using Constraints (UG903).

Architecture Support
All architectures.
Applicable Objects
Cells (get_cells)
”GRID”: The RPM_GRID property and GRID keyword combine to inform the Vivado Design Suite that the specified RLOCs are absolute grid coordinates from the target device, rather than the relative coordinates usually specified by RLOC.


Verilog Syntax

Place the Verilog attribute immediately before the module or instantiation. Specify as follows:

(* RPM_GRID = "GRID" *)

Verilog Example:

module iddr_regs (
input	clk, d, output y, z

(* RLOC = "X130Y195" *) IDDR ireg (.C(clk_i), .D(d), .Q1(q1), .Q2(q2));
defparam ireg.DDR_CLK_EDGE = "SAME_EDGE";
(* RLOC = "X147Y194" *)	FD q1reg (.C(clk_i), .D(q1), .Q(y));
(* RLOC = "X147Y194", RPM_GRID = "GRID" *) FD q2reg (.C(clk_i), .D(q2), .Q(z));

endmodule // iddr_regs
VHDL Syntax

To use the RPM_GRID system, first define the attribute, then add the attribute to one of the design elements:

attribute RPM_GRID of ram0 : label is "GRID";

Declare the VHDL constraint as follows:

attribute RPM_GRID : string;

Specify the VHDL constraint as follows:

attribute RPM_GRID of {component_name | entity_name} :
{component|entity} is “GRID”;
XDC Syntax

The RPM_GRID property is assigned in the RTL source file, and cannot be defined in XDC files or with Tcl commands. However, for XDC macros, the corresponding construct is the -absolute_grid option used with the update_macros command.

Affected Steps

  • Logical to Physical Mapping
  • Place Design
  • Synthesis