写一个 xilinx AXI4-lite 接口控制SPI接口的控制器
时间: 2024-05-16 13:18:32 浏览: 165
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以下是一个简单的 Xilinx AXI4-lite 接口控制 SPI 接口的控制器的代码示例:
```verilog
module spi_controller (
input aclk,
input aresetn,
input [7:0] tx_data,
output reg [7:0] rx_data,
input cs_n,
input sclk,
input mosi,
output reg miso
);
// AXI4-lite slave interface
reg [31:0] axi_awaddr;
reg [2:0] axi_awprot;
reg axi_awvalid, axi_awready;
reg [31:0] axi_araddr;
reg [2:0] axi_arprot;
reg axi_arvalid, axi_arready;
reg [31:0] axi_wdata;
reg [3:0] axi_wstrb;
reg axi_wvalid, axi_wready;
reg [31:0] axi_rdata;
reg axi_rvalid, axi_rready;
// Control signals for the SPI interface
reg [7:0] tx_reg;
reg [7:0] rx_reg;
reg [3:0] bit_count;
reg spi_busy;
// State machine states
localparam IDLE = 2'b00;
localparam WRITE = 2'b01;
localparam READ = 2'b10;
reg [1:0] state;
always @ (posedge aclk) begin
if (!aresetn) begin
state <= IDLE;
axi_awready <= 1'b0;
axi_arready <= 1'b0;
axi_wready <= 1'b0;
axi_rvalid <= 1'b0;
spi_busy <= 1'b0;
bit_count <= 0;
end else begin
case (state)
IDLE: begin
if (axi_awvalid && !spi_busy) begin
axi_awready <= 1'b1;
axi_arready <= 1'b1;
state <= WRITE;
tx_reg <= tx_data;
rx_reg <= 8'h00;
bit_count <= 8;
spi_busy <= 1'b1;
end else if (axi_arvalid && !spi_busy) begin
axi_awready <= 1'b1;
axi_arready <= 1'b1;
state <= READ;
tx_reg <= 8'h00;
rx_reg <= 8'h00;
bit_count <= 8;
spi_busy <= 1'b1;
end else begin
axi_awready <= 1'b0;
axi_arready <= 1'b0;
spi_busy <= 1'b0;
end
end
WRITE: begin
if (bit_count > 0) begin
mosi <= tx_reg[bit_count-1];
sclk <= 1'b0;
bit_count <= bit_count - 1;
end else begin
sclk <= 1'b1;
rx_reg <= {rx_reg[6:0], miso};
state <= IDLE;
axi_rdata <= rx_reg;
axi_rvalid <= 1'b1;
spi_busy <= 1'b0;
end
end
READ: begin
if (bit_count > 0) begin
mosi <= 1'b0;
sclk <= 1'b0;
bit_count <= bit_count - 1;
end else begin
sclk <= 1'b1;
rx_reg <= {rx_reg[6:0], miso};
state <= IDLE;
axi_rdata <= rx_reg;
axi_rvalid <= 1'b1;
spi_busy <= 1'b0;
end
end
default: state <= IDLE;
endcase
end
end
// AXI4-lite slave interface logic
assign axi_awready = (state == IDLE) && !spi_busy;
assign axi_arready = (state == IDLE) && !spi_busy;
assign axi_wready = (state == IDLE) && !spi_busy;
assign axi_rdata = axi_awaddr;
always @ (posedge aclk) begin
if (!aresetn) begin
axi_awready <= 1'b0;
axi_arready <= 1'b0;
axi_wready <= 1'b0;
axi_rvalid <= 1'b0;
end else begin
if (axi_awvalid && !spi_busy) begin
axi_awready <= 1'b0;
axi_awaddr <= axi_awaddr;
axi_awprot <= axi_awprot;
end
if (axi_arvalid && !spi_busy) begin
axi_arready <= 1'b0;
axi_araddr <= axi_araddr;
axi_arprot <= axi_arprot;
end
if (axi_wvalid && !spi_busy) begin
axi_wready <= 1'b0;
axi_wdata <= axi_wdata;
axi_wstrb <= axi_wstrb;
end
if (axi_rready) begin
axi_rvalid <= 1'b0;
end
end
end
// SPI interface logic
always @ (posedge sclk) begin
if (cs_n == 1'b0) begin
miso <= 1'b0;
end else if (spi_busy) begin
miso <= rx_reg[7];
end else begin
miso <= 1'b1;
end
end
endmodule
```
此代码使用 AXI4-lite 接口控制 SPI 接口,支持写入和读取操作。在 IDLE 状态下,如果 AXI4-lite 接收到写入请求,则将状态切换到 WRITE 状态,并在 SPI 接口上发送数据,然后将状态切换回 IDLE 状态,并将数据返回到 AXI4-lite 接口。如果接收到读取请求,则将状态切换到 READ 状态,并从 SPI 接口读取数据,然后将状态切换回 IDLE 状态,并将数据返回到 AXI4-lite 接口。SPI 接口的 MOSI 和 MISO 信号由时钟信号 SCLK 控制。注意,此代码仅供参考,并且可能需要根据您的具体要求进行修改。
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