diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/rtl/toggle.v | 92 | ||||
| -rw-r--r-- | src/tb/tb_toggle.v | 110 |
2 files changed, 202 insertions, 0 deletions
diff --git a/src/rtl/toggle.v b/src/rtl/toggle.v new file mode 100644 index 0000000..548b85e --- /dev/null +++ b/src/rtl/toggle.v @@ -0,0 +1,92 @@ +//====================================================================== +// +// toggle +// ------ +// gpio pin toggler. +// +// +// Author: Joachim Strombergson +// Copyright (c) 2018, NORDUnet A/S +// 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 the NORDUnet nor the names of its contributors may +// be used to endorse or promote products derived from this software +// without specific prior written permission. +// +// 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 +// HOLDER 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. +// +//====================================================================== + +module toggle + + ( + input wire sys_clk, + input wire reset_n, + output wire [7 : 0] gpio_b + ); + + localparam TOGGLE_DELAY_CYCLES = 100; + + reg [7 : 0] toggle_ctr_reg; + reg [7 : 0] toggle_ctr_new; + + reg toggle_reg; + reg toggle_we; + + assign gpio_b = {7'b1010101, toggle_reg}; + + always @(posedge sys_clk) + begin: sys_clk_toggle_reg_update + if (!reset_n) + begin + toggle_ctr_reg <= 32'h0; + toggle_reg <= 1'b0; + end + else + begin + toggle_ctr_reg <= toggle_ctr_new; + + if (toggle_we) + toggle_reg <= ~toggle_reg; + end + end + + always @* + begin : sys_clk_toggle + if (toggle_ctr_reg == TOGGLE_DELAY_CYCLES) + begin + toggle_ctr_new = 32'h0; + toggle_we = 1'b1; + end + else + begin + toggle_ctr_new = toggle_ctr_reg + 1'b1; + toggle_we = 1'b0; + end + end + +endmodule // toggle + +//====================================================================== +// EOF toggle.v +//====================================================================== diff --git a/src/tb/tb_toggle.v b/src/tb/tb_toggle.v new file mode 100644 index 0000000..0f3a9ad --- /dev/null +++ b/src/tb/tb_toggle.v @@ -0,0 +1,110 @@ +//====================================================================== +// +// tb_toggle +// --------- +// Testbench for the gpio pin toggler. +// +// +// Author: Joachim Strombergson +// Copyright (c) 2018, NORDUnet A/S +// 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 the NORDUnet nor the names of its contributors may +// be used to endorse or promote products derived from this software +// without specific prior written permission. +// +// 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 +// HOLDER 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. +// +//====================================================================== + +module tb_toggle(); + + parameter CLK_HALF_PERIOD = 1; + parameter CLK_PERIOD = 2 * CLK_HALF_PERIOD; + + reg tb_sys_clk; + reg tb_reset_n; + wire [7 : 0] tb_gpio_b; + reg [31 : 0] cycle_ctr; + + toggle dut( + .sys_clk(tb_sys_clk), + .reset_n(tb_reset_n), + .gpio_b(tb_gpio_b) + ); + + + //---------------------------------------------------------------- + // clk_gen + // + // Always running clock generator process. + //---------------------------------------------------------------- + always + begin : clk_gen + #CLK_HALF_PERIOD; + tb_sys_clk = !tb_sys_clk; + end // clk_gen + + + //---------------------------------------------------------------- + // sys_monitor() + // + // An always running process that creates a cycle counter and + // conditionally displays information about the DUT. + //---------------------------------------------------------------- + always + begin : sys_monitor + cycle_ctr = cycle_ctr + 1; + + #(CLK_PERIOD); + + $display("cycle: 0x%016x gpio_b: 0x%08x toggle_ctr: 0x%08x toggle_reg: 0x%01x", + cycle_ctr, tb_gpio_b, dut.toggle_ctr_reg, dut.toggle_reg); + end + + + //---------------------------------------------------------------- + // init_sim() + // + // Initialize all counters and testbed functionality as well + // as setting the DUT inputs to defined values. + //---------------------------------------------------------------- + initial + begin + cycle_ctr = 0; + tb_sys_clk = 0; + tb_reset_n = 0; + + #(CLK_PERIOD * 10); + + tb_reset_n = 1; + + #(CLK_PERIOD * 10000); + $finish; + end + +endmodule // tb_toggle + +//====================================================================== +// EOF tb_toggle.v +//====================================================================== |