155 lines
3.2 KiB
Verilog
155 lines
3.2 KiB
Verilog
/* Copyright 2024 (C) Peter McGoron
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*
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* This file is a part of Upsilon, a free and open source software project.
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* For license terms, refer to the files in `doc/copying` in the Upsilon
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* source distribution.
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*/
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module waveform_sim #(
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parameter RAM_START_ADDR = 32'h0,
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parameter SPI_START_ADDR = 32'h10000000,
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parameter COUNTER_MAX_WID = 16,
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parameter TIMER_WID = 16
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) (
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input clk,
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/* Waveform output control */
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input run,
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input force_stop,
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output [COUNTER_MAX_WID-1:0] cntr,
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input do_loop,
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output finished,
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output ready,
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input [COUNTER_MAX_WID-1:0] wform_size,
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output [TIMER_WID-1:0] timer,
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input [TIMER_WID-1:0] timer_spacing,
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/* data requests to Verilator */
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output reg [32-1:0] offset,
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output reg [32-1:0] spi_data,
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input [32-1:0] ram_data,
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output reg [1:0] enable,
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input ram_finished,
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/* Misc */
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input [32-1:0] spi_max_wait
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);
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wire [32-1:0] wb_adr;
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wire wb_cyc;
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wire wb_we;
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wire wb_stb;
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wire [32-1:0] wb_dat_w;
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reg [32-1:0] wb_dat_r;
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wire [4-1:0] wb_sel;
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reg wb_ack = 0;
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waveform #(
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.RAM_START_ADDR(RAM_START_ADDR),
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.SPI_START_ADDR(SPI_START_ADDR),
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.COUNTER_MAX_WID(COUNTER_MAX_WID),
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.TIMER_WID(TIMER_WID)
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) wf (
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.clk(clk),
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.run(run),
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.force_stop(force_stop),
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.cntr(cntr),
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.do_loop(do_loop),
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.finished(finished),
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.ready(ready),
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.wform_size(wform_size),
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.timer(timer),
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.timer_spacing(timer_spacing),
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.wb_adr(wb_adr),
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.wb_cyc(wb_cyc),
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.wb_we(wb_we),
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.wb_stb(wb_stb),
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.wb_dat_w(wb_dat_w),
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.wb_dat_r(wb_dat_r),
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.wb_ack(wb_ack),
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.wb_sel(wb_sel)
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);
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reg [32-1:0] spi_cntr = 0;
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reg spi_armed = 0;
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reg spi_running = 0;
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reg spi_ready_to_arm = 1;
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reg spi_finished = 0;
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/* SPI Delay simulation */
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always @ (posedge clk) if ((spi_armed || spi_running) && !spi_finished) begin
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spi_running <= 1;
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spi_ready_to_arm <= 0;
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if (spi_cntr == spi_max_wait) begin
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spi_cntr <= 0;
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spi_finished <= 1;
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end else begin
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spi_cntr <= spi_cntr + 1;
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end
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end else if (spi_finished) begin
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spi_running <= 0;
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if (!spi_armed) begin
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spi_finished <= 0;
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spi_ready_to_arm <= 1;
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end
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end
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/* Bus handlers */
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always @* if (wb_we && wb_sel != 4'b1111)
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$error("Write request without writing entire word");
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always @ (posedge clk) if (wb_cyc & wb_stb & ~wb_ack) begin
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if (wb_adr >= SPI_START_ADDR) case (wb_adr)
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SPI_START_ADDR | 32'h4: if (wb_we) begin
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spi_armed <= wb_dat_w[0];
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wb_ack <= 1;
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end else begin
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wb_dat_r[0] <= spi_armed;
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wb_ack <= 1;
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end
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SPI_START_ADDR | 32'hC: begin
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if (!wb_we) $error("Waveform should never read the to_slave register");
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/* Write SPI Data to verilator immediately, but have a counter
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* running in the background to simulate SPI transfer */
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spi_data <= wb_dat_w;
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enable <= 2'b10;
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if (ram_finished) begin
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enable <= 0;
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wb_ack <= 1;
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end
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end
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SPI_START_ADDR | 32'h10: begin
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if (wb_we) $error("Blocking SPI status check is read only register");
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if (spi_ready_to_arm || spi_finished) begin
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wb_dat_r[0] <= spi_ready_to_arm;
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wb_dat_r[1] <= spi_finished;
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wb_ack <= 1;
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end
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end
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default: begin
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$error("Invalid SPI address");
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end
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endcase else begin
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offset <= wb_adr;
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enable <= 2'b01;
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if (ram_finished) begin
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wb_dat_r <= ram_data;
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enable <= 0;
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wb_ack <= 1;
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end
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end
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end else if (~wb_cyc) begin
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wb_ack <= 0;
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end
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initial begin
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$dumpfile("waveform.fst");
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$dumpvars;
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end
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endmodule
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