VHDL: Dual-Port ROM

This example describes a 256-bit x 8-bit dual-port ROM design with two address ports for read operations in VHDL. Synthesis tools are able to detect ROM designs in the HDL code and automatically infer the altsyncram or lpm_rom megafunctions depending on the target device architecture.

Figure 1. Dual-port rom top-level diagram.

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Table 1. Dual-Port ROM Port Listing

Port Name Type Description
addr_a[7:0], addr_b[7:0] Input 8-bit read address inputs for port A and port B
clk Input Clock input
q_a[7:0], q_b[7:0] Output 8-bit data outputs for port A and port B