doom_riscv/projects/riscv_usb/rtl/soc_spram.v

/*
 * soc_spram.v
 *
 * vim: ts=4 sw=4
 *
 * Copyright (C) 2019  Sylvain Munaut <tnt@246tNt.com>
 * All rights reserved.
 *
 * BSD 3-clause, see LICENSE.bsd
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the <organization> nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

`default_nettype none

module soc_spram (
	input  wire [13:0] addr,
	output wire [31:0] rdata,
	input  wire [31:0] wdata,
	input  wire [ 3:0] wmsk,
	input  wire we,
	input  wire clk
);

	wire [3:0] msk_msb = { wmsk[3], wmsk[3], wmsk[2], wmsk[2] };
	wire [3:0] msk_lsb = { wmsk[1], wmsk[1], wmsk[0], wmsk[0] };

	SB_SPRAM256KA spram_msb_I (
		.DATAIN(wdata[31:16]),
		.ADDRESS(addr[13:0]),
		.MASKWREN(msk_msb),
		.WREN(we),
		.CHIPSELECT(1'b1),
		.CLOCK(clk),
		.STANDBY(1'b0),
		.SLEEP(1'b0),
		.POWEROFF(1'b1),
		.DATAOUT(rdata[31:16])
	);

	SB_SPRAM256KA spram_lsb_I (
		.DATAIN(wdata[15:0]),
		.ADDRESS(addr[13:0]),
		.MASKWREN(msk_lsb),
		.WREN(we),
		.CHIPSELECT(1'b1),
		.CLOCK(clk),
		.STANDBY(1'b0),
		.SLEEP(1'b0),
		.POWEROFF(1'b1),
		.DATAOUT(rdata[15:0])
	);

endmodule // soc_spram