/*	
	StriVe housekeeping SPI testbench.
*/

`timescale 1 ns / 1 ps

`include "caravel.v"
`include "spiflash.v"
`include "tbuart.v"

module hkspi_tb;
	reg clock;
	reg SDI, CSB, SCK, RSTB;

	wire [1:0] gpio;

	wire flash_csb;
	wire flash_clk;
	wire flash_io0;
	wire flash_io1;
	wire flash_io2;
	wire flash_io3;

	wire SDO;

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

	initial begin
		clock = 0;
	end

    // The main testbench is here.  Put the housekeeping SPI into
    // pass-thru mode and read several bytes from the flash SPI.

    // First define tasks for SPI functions

	task start_csb;
	    begin
		SCK <= 1'b0;
		SDI <= 1'b0;
		CSB <= 1'b0;
		#50;
	    end
	endtask

	task end_csb;
	    begin
		SCK <= 1'b0;
		SDI <= 1'b0;
		CSB <= 1'b1;
		#50;
	    end
	endtask

	task write_byte;
	    input [7:0] odata;
	    begin
		SCK <= 1'b0;
		for (i=7; i >= 0; i--) begin
		    #50;
		    SDI <= odata[i];
                    #50;
		    SCK <= 1'b1;
                    #100;
		    SCK <= 1'b0;
		end
	    end
	endtask

	task read_byte;
	    output [7:0] idata;
	    begin
		SCK <= 1'b0;
		SDI <= 1'b0;
		for (i=7; i >= 0; i--) begin
		    #50;
                    idata[i] = SDO;
                    #50;
		    SCK <= 1'b1;
                    #100;
		    SCK <= 1'b0;
		end
	    end
	endtask

	task read_write_byte
	    (input [7:0] odata,
	    output [7:0] idata);
	    begin
		SCK <= 1'b0;
		for (i=7; i >= 0; i--) begin
		    #50;
		    SDI <= odata[i];
                    idata[i] = SDO;
                    #50;
		    SCK <= 1'b1;
                    #100;
		    SCK <= 1'b0;
		end
	    end
	endtask
	
	integer i;

    // Now drive the digital signals on the housekeeping SPI
	reg [7:0] tbdata;

	initial begin
	    $dumpfile("hkspi.vcd");
	    $dumpvars(0, hkspi_tb);

	    CSB <= 1'b1;
	    SCK <= 1'b0;
	    SDI <= 1'b0;
	    RSTB <= 1'b0;

	    // Delay, then bring chip out of reset
	    #1000;
	    RSTB <= 1'b1;
	    #2000;

        // First do a normal read from the housekeeping SPI to
	    // make sure the housekeeping SPI works.

		start_csb();
		write_byte(8'h40);	// Read stream command
		write_byte(8'h03);	// Address (register 3 = product ID)
	    read_byte(tbdata);
	    end_csb();
	    #10;
	    $display("Read data = 0x%02x (should be 0x05)", tbdata);

	    // Toggle external reset
		start_csb();
		write_byte(8'h80);	// Write stream command
		write_byte(8'h07);	// Address (register 7 = external reset)
		write_byte(8'h01);	// Data = 0x01 (apply external reset)
		end_csb();

		start_csb();
		write_byte(8'h80);	// Write stream command
		write_byte(8'h07);	// Address (register 7 = external reset)
		write_byte(8'h00);	// Data = 0x00 (release external reset)
		end_csb();

	    // Read all registers (0 to 8)
		start_csb();
		write_byte(8'h40);	// Read stream command
		write_byte(8'h00);	// Address (register 3 = product ID)
	    read_byte(tbdata);
	    $display("Read register 0 = 0x%02x (should be 0x00)", tbdata);
		if(tbdata !== 8'h00) begin $display("Monitor: Test HK SPI (RTL) Failed"); $finish; end
	    read_byte(tbdata);
	    $display("Read register 1 = 0x%02x (should be 0x04)", tbdata);
		if(tbdata !== 8'h14) begin $display("Monitor: Test HK SPI (RTL) Failed"); $finish; end
	    read_byte(tbdata);
	    $display("Read register 2 = 0x%02x (should be 0x56)", tbdata);
		if(tbdata !== 8'h56) begin $display("Monitor: Test HK SPI (RTL) Failed, %02x", tbdata); $finish; end
	    read_byte(tbdata);
	    $display("Read register 3 = 0x%02x (should be 0x05)", tbdata);
		if(tbdata !== 8'h05) begin $display("Monitor: Test HK SPI (RTL) Failed"); $finish; end
	    read_byte(tbdata);
	    $display("Read register 4 = 0x%02x (should be 0x07)", tbdata);
		if(tbdata !== 8'h07) begin $display("Monitor: Test HK SPI (RTL) Failed"); $finish; end
	    read_byte(tbdata);
	    $display("Read register 5 = 0x%02x (should be 0x01)", tbdata);
		if(tbdata !== 8'h01) begin $display("Monitor: Test HK SPI (RTL) Failed"); $finish; end
	    read_byte(tbdata);
	    $display("Read register 6 = 0x%02x (should be 0x00)", tbdata);
		if(tbdata !== 8'h00) begin $display("Monitor: Test HK SPI (RTL) Failed"); $finish; end
	    read_byte(tbdata);
	    $display("Read register 7 = 0x%02x (should be 0x00)", tbdata);
		if(tbdata !== 8'h00) begin $display("Monitor: Test HK SPI (RTL) Failed"); $finish; end
	    read_byte(tbdata);
	    $display("Read register 8 = 0x%02x (should be 0x00)", tbdata);
		if(tbdata !== 8'h00) begin $display("Monitor: Test HK SPI (RTL) Failed"); $finish; end
		
        end_csb();

		$display("Monitor: Test HK SPI (RTL) Passed");

	    #10000;
 	    $finish;
	end

	wire VDD3V3;
	wire VDD1V8;
	wire VSS;

	assign VDD3V3 = 1'b1;
	assign VSS = 1'b0;
	assign VDD1V8 = 1'b1;

	caravel uut (
		.vdd3v3	  (VDD3V3),
		.vdd1v8	  (VDD1V8),
		.vss	  (VSS),
		.clock	  (clock),
		.SDI	  (SDI),
		.SDO	  (SDO),
		.CSB	  (CSB),
		.SCK	  (SCK),
		.ser_rx	  (1'b0),
		.ser_tx	  (tbuart_rx),
		.irq	  (1'b0),
		.gpio     (gpio),
		.flash_csb(flash_csb),
		.flash_clk(flash_clk),
		.flash_io0(flash_io0),
		.flash_io1(flash_io1),
		.flash_io2(flash_io2),
		.flash_io3(flash_io3),
		.RSTB	  (RSTB)
	);

	spiflash #(
		.FILENAME("hkspi.hex")
	) spiflash (
		.csb(flash_csb),
		.clk(flash_clk),
		.io0(flash_io0),
		.io1(flash_io1),
		.io2(flash_io2),
		.io3(flash_io3)
	);

	tbuart tbuart (
		.ser_rx(tbuart_rx)
	);
		
endmodule