module gpio_tb;

	reg clock;
	reg power1;
	reg power2;

	always #10 clock <= (clock === 1'b0);

	initial begin
		clock <= 0;
	end

	initial begin
		$dumpfile("gpio.vcd");
		$dumpvars(0, gpio_tb);

		// Repeat cycles of 1000 clock edges as needed to complete testbench
		repeat (25) begin
			repeat (1000) @(posedge clock);
			$display("+1000 cycles");
		end
		$display("%c[1;31m",27);
		`ifdef GL
			$display ("Monitor: Timeout, Test GPIO (GL) Failed");
		`else
			$display ("Monitor: Timeout, Test GPIO (RTL) Failed");
		`endif
		$display("%c[0m",27);
		$finish;
	end

	wire [37:0] mprj_io;	// Most of these are no-connects
	wire [15:0] checkbits;
	reg  [7:0] checkbits_lo;
	wire [7:0] checkbits_hi;

	assign mprj_io[23:16] = checkbits_lo;
	assign checkbits = mprj_io[31:16];
	assign checkbits_hi = checkbits[15:8];
	assign mprj_io[3] = 1'b1;       // Force CSB high.

	wire flash_csb;
	wire flash_clk;
	wire flash_io0;
	wire flash_io1;
	wire gpio;

	reg RSTB;

	// Transactor
	initial begin
		checkbits_lo <= {8{1'bz}};
		wait(checkbits_hi == 8'hA0);
		checkbits_lo <= 8'hF0;
		wait(checkbits_hi == 8'h0B);
		checkbits_lo <= 8'h0F;
		wait(checkbits_hi == 8'hAB);
		checkbits_lo <= 8'h0;
		repeat (1000) @(posedge clock);
		checkbits_lo <= 8'h1;
		repeat (1000) @(posedge clock);
		checkbits_lo <= 8'h3;
	end

	// Monitor
	initial begin
		wait(checkbits_hi == 8'hA0);
		wait(checkbits[7:0]  == 8'hF0);
		wait(checkbits_hi == 8'h0B);
		wait(checkbits[7:0]  == 8'h0F);
		wait(checkbits_hi == 8'hAB);
		wait(checkbits[7:0]  == 8'h00);
		wait(checkbits_hi == 8'h01);
		wait(checkbits[7:0]  == 8'h01);
		wait(checkbits_hi == 8'h02);
		wait(checkbits[7:0]  == 8'h03);
		wait(checkbits_hi == 8'h04);
		`ifdef GL
			$display("Monitor: Test GPIO (GL) Passed");
		`else
			$display("Monitor: Test GPIO (RTL) Passed");
		`endif
		$finish;
	end

	initial begin
		RSTB <= 1'b0;
		
		#1000;
		RSTB <= 1'b1;	    // Release reset
		#2000;
	end

	initial begin			// Power-up
		power1 <= 1'b0;
		power2 <= 1'b0;
		#200;
		power1 <= 1'b1;
		#200;
		power2 <= 1'b1;
	end
		

	always @(checkbits) begin
		#1 $display("GPIO state = %b (%d - %d)", checkbits,
				checkbits_hi, checkbits_lo);
	end

	wire VDD3V3;
	wire VDD1V8;
	wire VSS;

	assign VDD3V3 = power1;
	assign VDD1V8 = power2;
	assign VSS = 1'b0;

	// These are the mappings of mprj_io GPIO pads that are set to
	// specific functions on startup:
	//
	// JTAG      = mgmt_gpio_io[0]              (inout)
	// SDO       = mgmt_gpio_io[1]              (output)
	// SDI       = mgmt_gpio_io[2]              (input)
	// CSB       = mgmt_gpio_io[3]              (input)
	// SCK       = mgmt_gpio_io[4]              (input)
	// ser_rx    = mgmt_gpio_io[5]              (input)
	// ser_tx    = mgmt_gpio_io[6]              (output)
	// irq       = mgmt_gpio_io[7]              (input)

	caravel uut (
		.vddio	  (VDD3V3),
		.vssio	  (VSS),
		.vdda	  (VDD3V3),
		.vssa	  (VSS),
		.vccd	  (VDD1V8),
		.vssd	  (VSS),
		.vdda1    (VDD3V3),
		.vdda2    (VDD3V3),
		.vssa1	  (VSS),
		.vssa2	  (VSS),
		.vccd1	  (VDD1V8),
		.vccd2	  (VDD1V8),
		.vssd1	  (VSS),
		.vssd2	  (VSS),
		.clock	  (clock),
		.gpio     (gpio),
		.mprj_io  (mprj_io),
		.flash_csb(flash_csb),
		.flash_clk(flash_clk),
		.flash_io0(flash_io0),
		.flash_io1(flash_io1),
		.resetb	  (RSTB)
	);

	spiflash #(
		.FILENAME("gpio.hex")
	) spiflash (
		.csb(flash_csb),
		.clk(flash_clk),
		.io0(flash_io0),
		.io1(flash_io1),
		.io2(),			// not used
		.io3()			// not used
	);

endmodule