[Cryptech-Commits] [staging/core/comm/uart] 03/13: Adding testbench for the uart.
git at cryptech.is
git at cryptech.is
Tue Mar 17 13:13:37 UTC 2015
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paul at psgd.org pushed a commit to branch master
in repository staging/core/comm/uart.
commit 9fd0e15658b157bfc11ab611dffcf31cb9b8a85f
Author: Joachim Strömbergson <joachim at secworks.se>
Date: Thu Mar 13 15:41:17 2014 +0100
Adding testbench for the uart.
---
src/tb/tb_uart.v | 394 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 394 insertions(+)
diff --git a/src/tb/tb_uart.v b/src/tb/tb_uart.v
new file mode 100644
index 0000000..20a390e
--- /dev/null
+++ b/src/tb/tb_uart.v
@@ -0,0 +1,394 @@
+//======================================================================
+//
+// tb_uart.v
+// ---------
+// Testbench for the UART core.
+//
+//
+// Author: Joachim Strombergson
+// Copyright (c) 2014, SUNET
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or
+// without modification, are permitted provided that the following
+// conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//
+// 2. 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.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+// BUT NOT LIMITED TO, 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.
+//
+//======================================================================
+
+//------------------------------------------------------------------
+// Simulator directives.
+//------------------------------------------------------------------
+`timescale 1ns/10ps
+
+module tb_uart();
+
+ //----------------------------------------------------------------
+ // Internal constant and parameter definitions.
+ //----------------------------------------------------------------
+ parameter DEBUG = 0;
+ parameter VERBOSE = 0;
+
+ parameter CLK_HALF_PERIOD = 1;
+ parameter CLK_PERIOD = CLK_HALF_PERIOD * 2;
+
+
+ //----------------------------------------------------------------
+ // Register and Wire declarations.
+ //----------------------------------------------------------------
+ reg [31 : 0] cycle_ctr;
+ reg [31 : 0] error_ctr;
+ reg [31 : 0] tc_ctr;
+
+ reg tb_clk;
+ reg tb_reset_n;
+ reg tb_rxd;
+ wire tb_txd;
+ wire tb_rxd_syn;
+ wire [7 : 0] tb_rxd_data;
+ wire tb_rxd_ack;
+ wire tb_txd_syn;
+ wire [7 : 0] tb_txd_data;
+ wire tb_txd_ack;
+ reg tb_cs;
+ reg tb_we;
+ reg [3 : 0] tb_address;
+ reg [31 : 0] tb_write_data;
+ wire [31 : 0] tb_read_data;
+ wire tb_error;
+ wire [7 : 0] tb_debug;
+
+ reg txd_state;
+
+
+ //----------------------------------------------------------------
+ // Device Under Test.
+ //----------------------------------------------------------------
+ uart dut(
+ .clk(tb_clk),
+ .reset_n(tb_reset_n),
+
+ .rxd(tb_rxd),
+ .txd(tb_txd),
+
+ .rxd_syn(tb_rxd_syn),
+ .rxd_data(tb_rxd_data),
+ .rxd_ack(tb_rxd_ack),
+
+ // Internal transmit interface.
+ .txd_syn(tb_txd_syn),
+ .txd_data(tb_txd_data),
+ .txd_ack(tb_txd_ack),
+
+ // API interface.
+ .cs(tb_cs),
+ .we(tb_we),
+ .address(tb_address),
+ .write_data(tb_write_data),
+ .read_data(tb_read_data),
+ .error(tb_error),
+
+ .debug(tb_debug)
+ );
+
+ //----------------------------------------------------------------
+ // Concurrent assignments.
+ //----------------------------------------------------------------
+ // We connect the internal facing ports on the dut together.
+ assign tb_txd_syn = tb_rxd_syn;
+ assign tb_txd_data = tb_rxd_data;
+ assign tb_rxd_ack = tb_txd_ack;
+
+
+ //----------------------------------------------------------------
+ // clk_gen
+ //
+ // Clock generator process.
+ //----------------------------------------------------------------
+ always
+ begin : clk_gen
+ #CLK_HALF_PERIOD tb_clk = !tb_clk;
+ end // clk_gen
+
+
+ //----------------------------------------------------------------
+ // sys_monitor
+ //----------------------------------------------------------------
+ always
+ begin : sys_monitor
+ #(CLK_PERIOD);
+ if (DEBUG)
+ begin
+ dump_rx_state();
+ dump_tx_state();
+ $display("");
+ end
+ if (VERBOSE)
+ begin
+ $display("cycle: 0x%016x", cycle_ctr);
+ end
+ cycle_ctr = cycle_ctr + 1;
+ end
+
+
+ //----------------------------------------------------------------
+ // tx_monitor
+ //
+ // Observes what happens on the dut tx port and reports it.
+ //----------------------------------------------------------------
+ always @*
+ begin : tx_monitor
+ if ((!tb_txd) && txd_state)
+ begin
+ $display("txd going low.");
+ txd_state = 0;
+ end
+
+ if (tb_txd && (!txd_state))
+ begin
+ $display("txd going high");
+ txd_state = 1;
+ end
+ end
+
+
+ //----------------------------------------------------------------
+ // dump_dut_state()
+ //
+ // Dump the state of the dut when needed.
+ //----------------------------------------------------------------
+ task dump_dut_state();
+ begin
+ $display("State of DUT");
+ $display("------------");
+ $display("Inputs and outputs:");
+ $display("rxd = 0x%01x, txd = 0x%01x,",
+ dut.core.rxd, dut.core.txd);
+ $display("");
+
+ $display("Sample and data registers:");
+ $display("rxd_reg = 0x%01x, rxd_byte_reg = 0x%01x",
+ dut.core.rxd_reg, dut.core.rxd_byte_reg);
+ $display("");
+
+ $display("Counters:");
+ $display("rxd_bit_ctr_reg = 0x%01x, rxd_bitrate_ctr_reg = 0x%02x",
+ dut.core.rxd_bit_ctr_reg, dut.core.rxd_bitrate_ctr_reg);
+ $display("");
+
+
+ $display("Control signals and FSM state:");
+ $display("erx_ctrl_reg = 0x%02x",
+ dut.core.erx_ctrl_reg);
+ $display("");
+ end
+ endtask // dump_dut_state
+
+
+
+ //----------------------------------------------------------------
+ // dump_rx_state()
+ //
+ // Dump the state of the rx engine.
+ //----------------------------------------------------------------
+ task dump_rx_state();
+ begin
+ $display("rxd = 0x%01x, rxd_reg = 0x%01x, rxd_byte_reg = 0x%01x, rxd_bit_ctr_reg = 0x%01x, rxd_bitrate_ctr_reg = 0x%02x, rxd_syn = 0x%01x, erx_ctrl_reg = 0x%02x",
+ dut.core.rxd, dut.core.rxd_reg, dut.core.rxd_byte_reg, dut.core.rxd_bit_ctr_reg,
+ dut.core.rxd_bitrate_ctr_reg, dut.core.rxd_syn, dut.core.erx_ctrl_reg);
+ end
+ endtask // dump_dut_state
+
+
+
+ //----------------------------------------------------------------
+ // dump_tx_state()
+ //
+ // Dump the state of the tx engine.
+ //----------------------------------------------------------------
+ task dump_tx_state();
+ begin
+ $display("txd = 0x%01x, txd_reg = 0x%01x, txd_byte_reg = 0x%01x, txd_bit_ctr_reg = 0x%01x, txd_bitrate_ctr_reg = 0x%02x, txd_ack = 0x%01x, etx_ctrl_reg = 0x%02x",
+ dut.core.txd, dut.core.txd_reg, dut.core.txd_byte_reg, dut.core.txd_bit_ctr_reg,
+ dut.core.txd_bitrate_ctr_reg, dut.core.txd_ack, dut.core.etx_ctrl_reg);
+ end
+ endtask // dump_dut_state
+
+
+ //----------------------------------------------------------------
+ // reset_dut()
+ //----------------------------------------------------------------
+ task reset_dut();
+ begin
+ $display("*** Toggle reset.");
+ tb_reset_n = 0;
+ #(2 * CLK_PERIOD);
+ tb_reset_n = 1;
+ end
+ endtask // reset_dut
+
+
+ //----------------------------------------------------------------
+ // init_sim()
+ //
+ // Initialize all counters and testbed functionality as well
+ // as setting the DUT inputs to defined values.
+ //----------------------------------------------------------------
+ task init_sim();
+ begin
+ cycle_ctr = 0;
+ error_ctr = 0;
+ tc_ctr = 0;
+
+ tb_clk = 0;
+ tb_reset_n = 1;
+ tb_rxd = 1;
+ tb_cs = 0;
+ tb_we = 0;
+ tb_address = 4'h0;
+ tb_write_data = 32'h00000000;
+
+ txd_state = 1;
+ end
+ endtask // init_sim
+
+
+ //----------------------------------------------------------------
+ // transmit_byte
+ //
+ // Transmit a byte of data to the DUT receive port.
+ //----------------------------------------------------------------
+ task transmit_byte(input [7 : 0] data);
+ integer i;
+ begin
+ $display("*** Transmitting byte 0x%02x to the dut.", data);
+
+ #10;
+
+ // Start bit
+ $display("*** Transmitting start bit.");
+ tb_rxd = 0;
+ #(CLK_PERIOD * dut.core.DEFAULT_CLK_RATE);
+
+ // Send the bits LSB first.
+ for (i = 0 ; i < 8 ; i = i + 1)
+ begin
+ $display("*** Transmitting data[%1d] = 0x%01x.", i, data[i]);
+ tb_rxd = data[i];
+ #(CLK_PERIOD * dut.core.DEFAULT_CLK_RATE);
+ end
+
+ // Send two stop bits. I.e. two bit times high (mark) value.
+ $display("*** Transmitting two stop bits.");
+ tb_rxd = 1;
+ #(2 * CLK_PERIOD * dut.core.DEFAULT_CLK_RATE * dut.core.DEFAULT_STOP_BITS);
+ $display("*** End of transmission.");
+ end
+ endtask // transmit_byte
+
+
+ //----------------------------------------------------------------
+ // check_transmit
+ //
+ // Transmits a byte and checks that it was captured internally
+ // by the dut.
+ //----------------------------------------------------------------
+ task check_transmit(input [7 : 0] data);
+ begin
+ tc_ctr = tc_ctr + 1;
+
+ transmit_byte(data);
+
+ if (dut.core.rxd_byte_reg == data)
+ begin
+ $display("*** Correct data: 0x%01x captured by the dut.",
+ dut.core.rxd_byte_reg);
+ end
+ else
+ begin
+ $display("*** Incorrect data: 0x%01x captured by the dut Should be: 0x%01x.",
+ dut.core.rxd_byte_reg, data);
+ error_ctr = error_ctr + 1;
+ end
+ end
+ endtask // check_transmit
+
+
+ //----------------------------------------------------------------
+ // test_transmit
+ //
+ // Transmit a number of test bytes to the dut.
+ //----------------------------------------------------------------
+ task test_transmit();
+ begin
+ check_transmit(8'h55);
+ check_transmit(8'h42);
+ check_transmit(8'hde);
+ check_transmit(8'had);
+ end
+ endtask // test_transmit
+
+
+ //----------------------------------------------------------------
+ // display_test_result()
+ //
+ // Display the accumulated test results.
+ //----------------------------------------------------------------
+ task display_test_result();
+ begin
+ if (error_ctr == 0)
+ begin
+ $display("*** All %02d test cases completed successfully", tc_ctr);
+ end
+ else
+ begin
+ $display("*** %02d test cases did not complete successfully.", error_ctr);
+ end
+ end
+ endtask // display_test_result
+
+
+ //----------------------------------------------------------------
+ // uart_test
+ // The main test functionality.
+ //----------------------------------------------------------------
+ initial
+ begin : uart_test
+ $display(" -- Testbench for uart core started --");
+
+ init_sim();
+ dump_dut_state();
+ reset_dut();
+ dump_dut_state();
+
+ test_transmit();
+
+ display_test_result();
+ $display("*** Simulation done.");
+ $finish;
+ end // uart_test
+endmodule // tb_uart
+
+//======================================================================
+// EOF tb_uart.v
+//======================================================================
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