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//==============================================================

// Test reset circuit

//==============================================================

`timescale 100 ns/ 100 ns

module test_reset;

// ----------------- CLOCKS AND RESET -----------------

`define T #2

bit clk = 1;

initial repeat (40) #1 clk = ~clk;

// Specific to FPGA, some modules in the schematic need to be pre-initialized

reg fpga_reset = 1;

always_latch

    if (clk) fpga_reset <= 0;

//----------------------------------------------------------

// Input reset from the pin; state from the sequencer

//----------------------------------------------------------

logic reset_in = 0;

logic M1 = 0;

logic T2 = 0;

wire clrpc;            // Load 0 to PC

wire nreset;           // Internal inverted reset signal

// ----------------- TEST -------------------

initial begin

    // Test normal reset sequence - 3 clocks long

    `T reset_in = 1;

    `T `T `T reset_in = 0;

    `T assert(nreset==0);

    // Out of the reset for several more cycles

    // Check that the clrpc is set for the next 2 1/2 cycles (see waveform)

    `T assert(nreset==1 && clrpc==1);

    `T assert(nreset==1 && clrpc==1);

    `T assert(nreset==1 && clrpc==0);

    `T assert(nreset==1 && clrpc==0);

    `T assert(nreset==1 && clrpc==0);

    // Test special reset sequence: a reset pin is briefly

    // asserted at M1/T1 and CLRPC should hold until the next

    // M1/T2

    `T reset_in = 1; M1=1;

    `T reset_in = 0; M1=1; T2=1;

    `T               M1=1; T2=0;

    `T `T

    `T assert(nreset==1 && clrpc==1);

    `T               M1=1; T2=1;

    `T               M1=1; T2=0;

    `T assert(nreset==1 && clrpc==0);

    `T $display("End of test");

end

//--------------------------------------------------------------

// Instantiate DUT

//--------------------------------------------------------------

resets reset_block ( .* );

endmodule