pluto_hdl_adi/projects/fmcadc2/common/fmcadc2_spi.v

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// ***************************************************************************
// ***************************************************************************
// Copyright 2011(c) Analog Devices, Inc.
//
// All rights reserved.
//
// 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 Analog Devices, Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
// - The use of this software may or may not infringe the patent rights
// of one or more patent holders. This license does not release you
// from the requirement that you obtain separate licenses from these
// patent holders to use this software.
// - Use of the software either in source or binary form, must be run
// on or directly connected to an Analog Devices Inc. component.
//
// THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED.
//
// IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, INTELLECTUAL PROPERTY
// RIGHTS, 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.
// ***************************************************************************
// ***************************************************************************
`timescale 1ns/100ps
module fmcadc2_spi (
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spi_adf4355,
spi_adf4355_ce,
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spi_clk,
spi_csn,
spi_mosi,
spi_miso,
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spi_adc_csn,
spi_adc_clk,
spi_adc_sdio,
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spi_adf4355_data_or_csn_0,
spi_adf4355_clk_or_csn_1,
spi_adf4355_le_or_clk,
spi_adf4355_ce_or_sdio);
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// select (adf4355 = 0x1), (normal = 0x0)
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input spi_adf4355;
input spi_adf4355_ce;
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// 4 wire
input spi_clk;
input [ 2:0] spi_csn;
input spi_mosi;
output spi_miso;
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// adc interface (3 wire)
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output spi_adc_csn;
output spi_adc_clk;
inout spi_adc_sdio;
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// adf4355 or normal (AMP/EXT)
output spi_adf4355_data_or_csn_0;
output spi_adf4355_clk_or_csn_1;
output spi_adf4355_le_or_clk;
inout spi_adf4355_ce_or_sdio;
// internal registers
reg [ 5:0] spi_count = 'd0;
reg spi_rd_wr_n = 'd0;
reg spi_enable = 'd0;
// internal signals
wire spi_csn_s;
wire spi_enable_s;
// check on rising edge and change on falling edge
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assign spi_csn_s = & spi_csn;
assign spi_enable_s = spi_enable & ~spi_csn_s;
always @(posedge spi_clk or posedge spi_csn_s) begin
if (spi_csn_s == 1'b1) begin
spi_count <= 6'd0;
spi_rd_wr_n <= 1'd0;
end else begin
spi_count <= (spi_count < 6'h3f) ? spi_count + 1'b1 : spi_count;
if (spi_count == 6'd0) begin
spi_rd_wr_n <= spi_mosi;
end
end
end
always @(negedge spi_clk or posedge spi_csn_s) begin
if (spi_csn_s == 1'b1) begin
spi_enable <= 1'b0;
end else begin
if (spi_count == 6'd16) begin
spi_enable <= spi_rd_wr_n;
end
end
end
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assign spi_miso = ((spi_adc_sdio & ~spi_csn[0]) | (~spi_adf4355 &
spi_adf4355_ce_or_sdio & ~(spi_csn[1] & spi_csn[2])));
// adc interface (3 wire)
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assign spi_adc_csn = spi_csn[0];
assign spi_adc_clk = spi_clk;
assign spi_adc_sdio = (spi_enable_s == 1'b0) ? spi_mosi : 1'bz;
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// adf4355 or normal (AMP/EXT)
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assign spi_adf4355_data_or_csn_0 = (spi_adf4355 == 1'b1) ? spi_mosi : spi_csn[1];
assign spi_adf4355_clk_or_csn_1 = (spi_adf4355 == 1'b1) ? spi_clk : spi_csn[2];
assign spi_adf4355_le_or_clk = (spi_adf4355 == 1'b1) ? spi_csn[1] : spi_clk;
assign spi_adf4355_ce_or_sdio = (spi_adf4355 == 1'b1) ? spi_adf4355_ce :
((spi_enable_s == 1'b0) ? spi_mosi : 1'bz);
endmodule
// ***************************************************************************
// ***************************************************************************