RAM32X1D - 2024.1 English

Vivado Design Suite 7 Series FPGA and Zynq 7000 SoC Libraries Guide (UG953)

Document ID
UG953
Release Date
2024-05-30
Version
2024.1 English

Primitive: 32-Deep by 1-Wide Static Dual Port Synchronous RAM

Introduction

This design element is a 32-bit deep by 1-bit wide static dual port random access memory with synchronous write capability. The device has two separate address ports: the read address (DPRA4:DPRA0) and the write address (A4:A0). These two address ports are completely asynchronous. The read address controls the location of the data driven out of the output pin (DPO), and the write address controls the destination of a valid write transaction. When the write enable (WE) is Low, transitions on the write clock (WCLK) are ignored and data stored in the RAM is not affected. When WE is High, any positive transition on WCLK loads the data on the data input (D) into the memory cell selected by the 5-bit write address. For predictable performance, write address and data inputs must be stable before a Low-to-High WCLK transition. This RAM block assumes an active-High WCLK. WCLK can be active-High or active-Low. Any inverter placed on the WCLK input net is absorbed into the block. You can initialize RAM32X1D during configuration using the INIT attribute. Mode selection is shown in the following logic table.

The SPO output reflects the data in the memory cell addressed by A4:A0. The DPO output reflects the data in the memory cell addressed by DPRA4:DPRA0. The write process is not affected by the address on the read address port.

You can use the INIT attribute to specify the initial contents of the RAM. If left unspecified, the initial contents default to all zeros.

Logic Table

Inputs Outputs
WE (Mode) WCLK D SPO DPO
0 (read) X X data_a data_d
1 (read) 0 X data_a data_d
1 (read) 1 X data_a data_d
1 (write) D D data_d
1 (read) X data_a data_d

Design Entry Method

Instantiation Yes
Inference Recommended
IP Catalog No
Macro support No

Available Attributes

Attribute Type Allowed Values Default Description
INIT HEX Any 32-bit value All zeros Specifies the initial contents of the RAM.

VHDL Instantiation Template

Unless they already exist, copy the following two statements and paste them before the entity declaration.
Library UNISIM;
use UNISIM.vcomponents.all;

-- RAM32X1D: 32 x 1 positive edge write, asynchronous read
--              dual-port distributed RAM (Mapped to SliceM LUT6)
--              7 Series
-- Xilinx HDL Language Template, version 2024.1

RAM32X1D_inst : RAM32X1D
generic map (
   INIT => X"00000000") -- Initial contents of RAM
port map (
   DPO => DPO,     -- Read-only 1-bit data output
   SPO => SPO,     -- R/W 1-bit data output
   A0 => A0,       -- R/W address[0] input bit
   A1 => A1,       -- R/W address[1] input bit
   A2 => A2,       -- R/W address[2] input bit
   A3 => A3,       -- R/W address[3] input bit
   A4 => A4,       -- R/W address[4] input bit
   D => D,         -- Write 1-bit data input
   DPRA0 => DPRA0, -- Read-only address[0] input bit
   DPRA1 => DPRA1, -- Read-only address[1] input bit
   DPRA2 => DPRA2, -- Read-only address[2] input bit
   DPRA3 => DPRA3, -- Read-only address[3] input bit
   DPRA4 => DPRA4, -- Read-only address[4] input bit
   WCLK => WCLK,   -- Write clock input
   WE => WE        -- Write enable input
);

-- End of RAM32X1D_inst instantiation

Verilog Instantiation Template


// RAM32X1D: 32 x 1 positive edge write, asynchronous read dual-port
//           distributed RAM (Mapped to a SliceM LUT6)
//           7 Series
// Xilinx HDL Language Template, version 2024.1

RAM32X1D #(
   .INIT(32'h00000000) // Initial contents of RAM
) RAM32X1D_inst (
   .DPO(DPO),     // Read-only 1-bit data output
   .SPO(SPO),     // Rw/ 1-bit data output
   .A0(A0),       // Rw/ address[0] input bit
   .A1(A1),       // Rw/ address[1] input bit
   .A2(A2),       // Rw/ address[2] input bit
   .A3(A3),       // Rw/ address[3] input bit
   .A4(A4),       // Rw/ address[4] input bit
   .D(D),         // Write 1-bit data input
   .DPRA0(DPRA0), // Read-only address[0] input bit
   .DPRA1(DPRA1), // Read-only address[1] input bit
   .DPRA2(DPRA2), // Read-only address[2] input bit
   .DPRA3(DPRA3), // Read-only address[3] input bit
   .DPRA4(DPRA4), // Read-only address[4] input bit
   .WCLK(WCLK),   // Write clock input
   .WE(WE)        // Write enable input
);

// End of RAM32X1D_inst instantiation

Related Information

  • 7 Series FPGAs Configurable Logic Block User Guide (UG474)