module ad7794_sim ( input CLK, input CS, input DIN, output DOUT_RDY, input SCLK ); reg [31:0] value=0; reg [31:0] value_sr=0; always @(negedge SCLK or posedge CS) begin if (CS) begin value <= value + 1; value_sr <= value; end else if (!CS) value_sr <= {value_sr[30:0], 1'b0}; end reg [31:0] shifter; always @(posedge SCLK or posedge CS) begin if (CS) shifter <= {32{1'bx}}; else shifter <= {shifter, DIN}; end always @(posedge CS) $display("AD7794 simulator received word %8x", shifter); assign DOUT_RDY = CS ? 1'bz : value_sr[31]; endmodule