pluto_hdl_adi/library/axi_ad7175/ad7175_if.v

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// ***************************************************************************
// ***************************************************************************
// Copyright 2011(c) Analog Devices, Inc.
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//
// 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.
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//
// 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
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//------------------------------------------------------------------------------
//----------- Module Declaration -----------------------------------------------
//------------------------------------------------------------------------------
module ad7175_if
(
// Clock and Reset signals
input fpga_clk_i,
input adc_clk_i,
input reset_n_i,
// Conversion control signals
input start_conversion_i,
output [31:0] dma_data_o,
output dma_data_rdy_o,
// Transmit data on request signals
input start_transmission_i,
input [31:0] tx_data_i,
output tx_data_rdy_o,
// Read data on request signals
input start_read_i,
output [31:0] rx_data_o,
output rx_data_rdy_o,
// AD7175 IC control signals
input adc_sdo_i,
output adc_sdi_o,
output adc_cs_o,
output adc_sclk_o,
// ADC status
output reg adc_status_o
);
//------------------------------------------------------------------------------
//----------- Registers Declarations -------------------------------------------
//------------------------------------------------------------------------------
// State Machine Registers
reg [10:0] present_state; // Present FSM State
reg [10:0] next_state; // Next FSM State
reg [10:0] present_state_m1; // Used to synchronise FSM States between different clock domains
// SCLK Registers
reg [7:0] sclk_cnt; // Used to count SCLK Ticks
reg [7:0] sclk_demand; // Used to set number of SCLK Ticks
// Transmit Data Registers
reg [47:0] tx_data_reg; // Used to shift data out
reg [47:0] tx_data_reg_switch; // Used to select data that is being sent
reg tx_data_rdy_int; // Used to signal the end of a transmit cycle
// Receive Data Registers
reg [47:0] rx_data_reg; // Used to shift data in
reg [31:0] rx_read_data_reg; // Used to store read data
reg rx_data_rdy_int; // Used to signal the end of a read cycle
// Conversion Data Registers
reg [31:0] dma_rx_data_reg; // Used to store conversion result (STATUS_REG[31:24] + DATA_REG[23:0])
reg dma_rdy_int; // Used to signal the end of a conversion read
// Internal registers used for external ports
reg adc_sdi_o_int; // Used for adc_sdi_o
reg cs_int; // Used for adc_cs_o
//------------------------------------------------------------------------------
//----------- Wires Declarations -----------------------------------------------
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
//----------- Local Parameters -------------------------------------------------
//------------------------------------------------------------------------------
// ADC Controller State Machine States
parameter ADC_IDLE_STATE = 11'b00000000001; // Waits for Start Conversion / Start Transmission / Start Read
parameter ADC_WAIT_FOR_DATA_STATE = 11'b00000000010; // Waits for adc_sdo_i to go low (signals new data is available)
parameter ADC_PREP_READ_RESULT_STATE = 11'b00000000100; // Prepares data to perform Status + Data Register Read
parameter ADC_READ_RESULT_STATE = 11'b00000001000; // Reads Status + Data Register
parameter ADC_READ_RESULT_DONE_STATE = 11'b00000010000; // Signals completion of Status + Data Register Read
parameter ADC_PREP_SEND_DATA_STATE = 11'b00000100000; // Prepares data to perform Data Transmit
parameter ADC_SEND_DATA_STATE = 11'b00001000000; // Transmit Data
parameter ADC_SEND_DATA_DONE_STATE = 11'b00010000000; // Signals completion of Data Transmission
parameter ADC_PREP_READ_DATA_STATE = 11'b00100000000; // Prepares data to perform Data Read
parameter ADC_READ_DATA_STATE = 11'b01000000000; // Reads Data
parameter ADC_READ_DATA_DONE_STATE = 11'b10000000000; // Signals completion of Data Read
// Number of SCLK Periods required for Status + Data Read
parameter ADC_SCLK_PERIODS = 8'd48;
//------------------------------------------------------------------------------
//----------- Assign/Always Blocks ---------------------------------------------
//------------------------------------------------------------------------------
assign adc_sdi_o = adc_sdi_o_int;
assign adc_sclk_o = (((present_state_m1 == ADC_READ_RESULT_STATE)||(present_state_m1 == ADC_SEND_DATA_STATE)||(present_state_m1 == ADC_READ_DATA_STATE))&&(sclk_cnt != 8'd0)) ? adc_clk_i : 1'b1;
assign dma_data_o = dma_rx_data_reg;
assign dma_data_rdy_o = dma_rdy_int;
assign adc_cs_o = cs_int;
assign tx_data_rdy_o = tx_data_rdy_int;
assign rx_data_o = rx_read_data_reg;
assign rx_data_rdy_o = rx_data_rdy_int;
// Register States
always @(posedge fpga_clk_i)
begin
if(reset_n_i == 1'b0)
begin
present_state <= ADC_IDLE_STATE;
adc_status_o <= 1'b0;
end
else
begin
present_state <= next_state;
adc_status_o <= 1'b1;
end
end
// State switch logic
always @(posedge fpga_clk_i)
begin
next_state <= present_state;
case(present_state)
ADC_IDLE_STATE:
begin
// If transmit data is required
if(start_transmission_i == 1'b1)
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begin
next_state <= ADC_PREP_SEND_DATA_STATE;
end
// If read data is required
else if(start_read_i == 1'b1)
begin
next_state <= ADC_PREP_READ_DATA_STATE;
end
// If start conversion has been requested
else if(start_conversion_i == 1'b1)
begin
next_state <= ADC_WAIT_FOR_DATA_STATE;
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end
end
ADC_WAIT_FOR_DATA_STATE:
begin
// If new data is available
if(adc_sdo_i == 1'b0)
begin
next_state <= ADC_PREP_READ_RESULT_STATE;
end
// If transmit data is required
else if(start_transmission_i == 1'b1)
begin
next_state <= ADC_PREP_SEND_DATA_STATE;
end
// If read data is required
else if(start_read_i == 1'b1)
begin
next_state <= ADC_PREP_READ_DATA_STATE;
end
// If transmit data is not required anymore
else if(start_conversion_i == 1'b0)
begin
next_state <= ADC_IDLE_STATE;
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end
end
ADC_PREP_READ_RESULT_STATE:
begin
if(present_state_m1 == ADC_PREP_READ_RESULT_STATE)
begin
next_state <= ADC_READ_RESULT_STATE;
end
end
ADC_READ_RESULT_STATE:
begin
// If data has been sent
if(sclk_cnt == 8'd0)
begin
next_state <= ADC_READ_RESULT_DONE_STATE;
end
end
ADC_READ_RESULT_DONE_STATE:
begin
next_state <= ADC_IDLE_STATE;
end
ADC_PREP_SEND_DATA_STATE:
begin
if(present_state_m1 == ADC_PREP_SEND_DATA_STATE)
begin
next_state <= ADC_SEND_DATA_STATE;
end
end
ADC_SEND_DATA_STATE:
begin
// If data has been sent
if(sclk_cnt == 8'd0)
begin
next_state <= ADC_SEND_DATA_DONE_STATE;
end
end
ADC_SEND_DATA_DONE_STATE:
begin
next_state <= ADC_IDLE_STATE;
end
ADC_PREP_READ_DATA_STATE:
begin
if(present_state_m1 == ADC_PREP_READ_DATA_STATE)
begin
next_state <= ADC_READ_DATA_STATE;
end
end
ADC_READ_DATA_STATE:
begin
// If data has been sent
if(sclk_cnt == 8'd0)
begin
next_state <= ADC_READ_DATA_DONE_STATE;
end
end
ADC_READ_DATA_DONE_STATE:
begin
next_state <= ADC_IDLE_STATE;
end
default:
begin
next_state <= ADC_IDLE_STATE;
end
endcase
end
// State output logic
always @(posedge fpga_clk_i)
begin
if(reset_n_i == 1'b0)
begin
dma_rdy_int <= 1'b0;
cs_int <= 1'b1;
tx_data_rdy_int <= 1'b0;
rx_data_rdy_int <= 1'b0;
end
else
begin
case(present_state)
ADC_IDLE_STATE:
begin
dma_rdy_int <= 1'b0;
tx_data_rdy_int <= 1'b0;
rx_data_rdy_int <= 1'b0;
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cs_int <= 1'b1;
end
ADC_WAIT_FOR_DATA_STATE:
begin
cs_int <= 1'b0;
end
ADC_PREP_READ_RESULT_STATE:
begin
dma_rdy_int <= 1'b0;
tx_data_reg_switch <= 48'h400044000000;
cs_int <= 1'b0;
end
ADC_READ_RESULT_STATE:
begin
dma_rdy_int <= 1'b0;
cs_int <= 1'b0;
end
ADC_READ_RESULT_DONE_STATE:
begin
// Final data = Status Reg + Data Reg
dma_rx_data_reg <= {rx_data_reg[39:32], rx_data_reg[23:0]};
dma_rdy_int <= 1'b1;
cs_int <= 1'b1;
end
ADC_PREP_SEND_DATA_STATE:
begin
// Maximum 32 bits transmission (that is why I add 16'd0 to the LSB)
tx_data_rdy_int <= 1'b1;
cs_int <= 1'b1;
tx_data_reg_switch <= {tx_data_i, 16'd0};
end
ADC_SEND_DATA_STATE:
begin
tx_data_rdy_int <= 1'b0;
cs_int <= 1'b0;
end
ADC_SEND_DATA_DONE_STATE:
begin
tx_data_rdy_int <= 1'b1;
cs_int <= 1'b1;
end
ADC_PREP_READ_DATA_STATE:
begin
// Maximum 32 bits transmission (that is why I add 16'd0 to the LSB)
cs_int <= 1'b1;
rx_data_rdy_int <= 1'b1;
tx_data_reg_switch <= {2'b01, tx_data_i[29:0], 16'd0};
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end
ADC_READ_DATA_STATE:
begin
cs_int <= 1'b0;
rx_data_rdy_int <= 1'b0;
end
ADC_READ_DATA_DONE_STATE:
begin
rx_read_data_reg <= rx_data_reg[31:0];
cs_int <= 1'b1;
rx_data_rdy_int <= 1'b1;
end
default:
begin
tx_data_rdy_int <= 1'b0;
rx_data_rdy_int <= 1'b0;
dma_rdy_int <= 1'b0;
cs_int <= 1'b1;
end
endcase
end
end
// Synchronise States between different clock domains
always @(posedge adc_clk_i)
begin
present_state_m1 <= present_state;
end
// Select size of transfered data according to desired registers (see AD7176_2 Datasheet for details)
always @(posedge fpga_clk_i)
begin
case(tx_data_i[29:24])
6'h00:
begin
sclk_demand <= 8'd16;
end
6'h01, 6'h02, 6'h06, 6'h07, 6'h10, 6'h11, 6'h12, 6'h13, 6'h20, 6'h21, 6'h22, 6'h23, 6'h28, 6'h29, 6'h2a, 6'h2b:
begin
sclk_demand <= 8'd24;
end
6'h03, 6'h04, 6'h30, 6'h31, 6'h32, 6'h33, 6'h38, 6'h39, 6'h3a, 6'h3b:
begin
sclk_demand <= 8'd32;
end
default:
begin
sclk_demand <= 8'd16;
end
endcase
end
// Serial Data In
always @(posedge adc_clk_i)
begin
if((present_state_m1 == ADC_READ_RESULT_STATE)||(present_state_m1 == ADC_SEND_DATA_STATE)||(present_state_m1 == ADC_READ_DATA_STATE))
begin
sclk_cnt <= sclk_cnt - 8'd1;
rx_data_reg <= {rx_data_reg[46:0], adc_sdo_i};
end
else
begin
if((present_state_m1 == ADC_PREP_SEND_DATA_STATE)||(present_state_m1 == ADC_PREP_READ_DATA_STATE))
begin
sclk_cnt <= sclk_demand;
end
else
begin
sclk_cnt <= ADC_SCLK_PERIODS;
end
if(present_state_m1 == ADC_IDLE_STATE)
begin
rx_data_reg <= 48'd0;
end
end
end
// Serial Data Out
always @(negedge adc_clk_i)
begin
if((present_state_m1 == ADC_READ_RESULT_STATE)||(present_state_m1 == ADC_SEND_DATA_STATE)||(present_state_m1 == ADC_READ_DATA_STATE))
begin
adc_sdi_o_int <= tx_data_reg[47];
tx_data_reg <= {tx_data_reg[46:0], 1'b0};
end
else
begin
tx_data_reg <= tx_data_reg_switch;
end
end
endmodule