使用Verilog实现一个带有spicmd，spiadr，spilen，spidum，intcfg端口的spi协议

以下是一个简单的Verilog代码，实现了一个带有spicmd，spiadr，spilen，spidum，intcfg端口的spi协议。

module spi_protocol(clk, rst, spi_cs, spi_sclk, spi_mosi, spi_miso, spicmd, spiadr, spilen, spidum, intcfg);
input clk, rst;
output spi_cs, spi_sclk, spi_mosi, spi_miso;
input spicmd, spiadr, spilen, spidum, intcfg;
reg [7:0] cmd_reg;
reg [7:0] adr_reg;
reg [7:0] len_reg;
reg [7:0] dum_reg;
reg int_enable;
reg [7:0] spi_data;
reg [7:0] tx_data;
reg [7:0] rx_data;
reg [7:0] data_cnt;
reg [7:0] bit_cnt;
reg [7:0] state;
wire sclk_out;

assign spi_cs = ~spiadr & ~spilen;
assign spi_miso = (state == 2) ? rx_data[7] : 1'bZ;
assign sclk_out = (state == 1) ? spi_sclk : 1'b0;

always @(posedge clk or posedge rst) begin
if (rst) begin
cmd_reg <= 8'b0;
adr_reg <= 8'b0;
len_reg <= 8'b0;
dum_reg <= 8'b0;
int_enable <= 1'b0;
spi_data <= 8'b0;
tx_data <= 8'b0;
rx_data <= 8'b0;
data_cnt <= 8'b0;
bit_cnt <= 8'b0;
state <= 8'h0;
end else begin
cmd_reg <= spicmd ? spi_data : cmd_reg;
adr_reg <= spiadr ? spi_data : adr_reg;
len_reg <= spilen ? spi_data : len_reg;
dum_reg <= spidum ? spi_data : dum_reg;
int_enable <= intcfg ? spi_data[0] : int_enable;

case (state)
8'h0: begin
if (~spi_cs) begin
state <= 8'h1;
tx_data <= cmd_reg;
bit_cnt <= 8'h8;
end
end
8'h1: begin
spi_sclk <= sclk_out;
if (sclk_out) begin
spi_mosi <= tx_data[7];
tx_data <= {1'b0, tx_data[7:1]};
bit_cnt <= bit_cnt - 1;
if (bit_cnt == 0) begin
state <= 8'h2;
tx_data <= adr_reg;
bit_cnt <= 8'h8;
end
end
end
8'h2: begin
spi_sclk <= sclk_out;
if (sclk_out) begin
spi_mosi <= tx_data[7];
tx_data <= {1'b0, tx_data[7:1]};
bit_cnt <= bit_cnt - 1;
if (bit_cnt == 0) begin
state <= 8'h3;
tx_data <= len_reg;
bit_cnt <= 8'h8;
data_cnt <= 8'b0;
end
end
end
8'h3: begin
spi_sclk <= sclk_out;
if (sclk_out) begin
spi_mosi <= tx_data[7];
tx_data <= {1'b0, tx_data[7:1]};
bit_cnt <= bit_cnt - 1;
if (bit_cnt == 0) begin
state <= 8'h4;
end
end
end
8'h4: begin
spi_sclk <= sclk_out;
if (sclk_out) begin
spi_mosi <= 1'b0;
bit_cnt <= bit_cnt - 1;
if (bit_cnt == 0) begin
state <= 8'h5;
bit_cnt <= 8'h8;
end
end
end
8'h5: begin
spi_sclk <= sclk_out;
if (sclk_out) begin
rx_data <= {rx_data[6:0], spi_miso};
bit_cnt <= bit_cnt - 1;
if (bit_cnt == 0) begin
state <= 8'h6;
end
end
end
8'h6: begin
spi_sclk <= sclk_out;
if (sclk_out) begin
tx_data <= {1'b0, dum_reg};
bit_cnt <= bit_cnt - 1;
if (bit_cnt == 0) begin
state <= 8'h7;
data_cnt <= 8'b0;
end
end
end
8'h7: begin
spi_sclk <= sclk_out;
if (sclk_out) begin
spi_mosi <= tx_data[7];
tx_data <= {1'b0, tx_data[7:1]};
bit_cnt <= bit_cnt - 1;
if (bit_cnt == 0) begin
state <= 8'h8;
end
end
end
8'h8: begin
spi_sclk <= sclk_out;
if (sclk_out) begin
if (data_cnt < len_reg) begin
state <= 8'h9;
bit_cnt <= 8'h8;
end else begin
state <= 8'h0;
spi_data <= 8'b0;
bit_cnt <= 8'h0;
if (int_enable) begin
// generate interrupt
end
end
end
end
8'h9: begin
spi_sclk <= sclk_out;
if (sclk_out) begin
spi_mosi <= 1'b0;
bit_cnt <= bit_cnt - 1;
if (bit_cnt == 0) begin
state <= 8'h5;
data_cnt <= data_cnt + 1;
end
end
end
endcase
end
end
endmodule