picorv32/picosoc/icebreaker_tb.v

123 lines
2.8 KiB
Verilog

/*
* PicoSoC - A simple example SoC using PicoRV32
*
* Copyright (C) 2017 Clifford Wolf <clifford@clifford.at>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
`timescale 1 ns / 1 ps
module testbench;
reg clk;
always #5 clk = (clk === 1'b0);
localparam ser_half_period = 53;
event ser_sample;
initial begin
$dumpfile("testbench.vcd");
$dumpvars(0, testbench);
repeat (6) begin
repeat (50000) @(posedge clk);
$display("+50000 cycles");
end
$finish;
end
integer cycle_cnt = 0;
always @(posedge clk) begin
cycle_cnt <= cycle_cnt + 1;
end
wire led1, led2, led3, led4, led5;
wire ledr_n, ledg_n;
wire [6:0] leds = {!ledg_n, !ledr_n, led5, led4, led3, led2, led1};
wire ser_rx;
wire ser_tx;
wire flash_csb;
wire flash_clk;
wire flash_io0;
wire flash_io1;
wire flash_io2;
wire flash_io3;
always @(leds) begin
#1 $display("%b", leds);
end
icebreaker #(
// We limit the amount of memory in simulation
// in order to avoid reduce simulation time
// required for intialization of RAM
.MEM_WORDS(256)
) uut (
.clk (clk ),
.led1 (led1 ),
.led2 (led2 ),
.led3 (led3 ),
.led4 (led4 ),
.led5 (led5 ),
.ledr_n (ledr_n ),
.ledg_n (ledg_n ),
.ser_rx (ser_rx ),
.ser_tx (ser_tx ),
.flash_csb(flash_csb),
.flash_clk(flash_clk),
.flash_io0(flash_io0),
.flash_io1(flash_io1),
.flash_io2(flash_io2),
.flash_io3(flash_io3)
);
spiflash spiflash (
.csb(flash_csb),
.clk(flash_clk),
.io0(flash_io0),
.io1(flash_io1),
.io2(flash_io2),
.io3(flash_io3)
);
reg [7:0] buffer;
always begin
@(negedge ser_tx);
repeat (ser_half_period) @(posedge clk);
-> ser_sample; // start bit
repeat (8) begin
repeat (ser_half_period) @(posedge clk);
repeat (ser_half_period) @(posedge clk);
buffer = {ser_tx, buffer[7:1]};
-> ser_sample; // data bit
end
repeat (ser_half_period) @(posedge clk);
repeat (ser_half_period) @(posedge clk);
-> ser_sample; // stop bit
if (buffer < 32 || buffer >= 127)
$display("Serial data: %d", buffer);
else
$display("Serial data: '%c'", buffer);
end
endmodule