今天为了熟悉axiLite的自定义ip核设计，
把LED和SW的往AXI总线输入输出定义在一个ip核中，
BD设计如下：
ip核顶层文件（增加了LED_Out和SW_In的定义）mygpio_v1.0.v：
module mygpio_v1_0 #
(
// Users to add parameters here // User parameters ends
// Do not modify the parameters beyond this line // Parameters of Axi Slave Bus Interface S00_AXI
parameter integer C_S00_AXI_DATA_WIDTH = 32,
parameter integer C_S00_AXI_ADDR_WIDTH = 4
)
(
// Users to add ports here
//*****************my code***********************************
input wire [7:0] SW_In,
output wire [7:0] LED_Out,
// User ports ends
// Do not modify the ports beyond this line // Ports of Axi Slave Bus Interface S00_AXI
input wire s00_axi_aclk,
input wire s00_axi_aresetn,
input wire [C_S00_AXI_ADDR_WIDTH-1 : 0] s00_axi_awaddr,
input wire [2 : 0] s00_axi_awprot,
input wire s00_axi_awvalid,
output wire s00_axi_awready,
input wire [C_S00_AXI_DATA_WIDTH-1 : 0] s00_axi_wdata,
input wire [(C_S00_AXI_DATA_WIDTH/8)-1 : 0] s00_axi_wstrb,
input wire s00_axi_wvalid,
output wire s00_axi_wready,
output wire [1 : 0] s00_axi_bresp,
output wire s00_axi_bvalid,
input wire s00_axi_bready,
input wire [C_S00_AXI_ADDR_WIDTH-1 : 0] s00_axi_araddr,
input wire [2 : 0] s00_axi_arprot,
input wire s00_axi_arvalid,
output wire s00_axi_arready,
output wire [C_S00_AXI_DATA_WIDTH-1 : 0] s00_axi_rdata,
output wire [1 : 0] s00_axi_rresp,
output wire s00_axi_rvalid,
input wire s00_axi_rready
);
// Instantiation of Axi Bus Interface S00_AXI
mygpio_v1_0_S00_AXI # (
.C_S_AXI_DATA_WIDTH(C_S00_AXI_DATA_WIDTH),
.C_S_AXI_ADDR_WIDTH(C_S00_AXI_ADDR_WIDTH)
) mygpio_v1_0_S00_AXI_inst (
//*****************************my code***************************
.SW_In(SW_In),
.LED_Out(LED_Out),
.S_AXI_ACLK(s00_axi_aclk),
.S_AXI_ARESETN(s00_axi_aresetn),
.S_AXI_AWADDR(s00_axi_awaddr),
.S_AXI_AWPROT(s00_axi_awprot),
.S_AXI_AWVALID(s00_axi_awvalid),
.S_AXI_AWREADY(s00_axi_awready),
.S_AXI_WDATA(s00_axi_wdata),
.S_AXI_WSTRB(s00_axi_wstrb),
.S_AXI_WVALID(s00_axi_wvalid),
.S_AXI_WREADY(s00_axi_wready),
.S_AXI_BRESP(s00_axi_bresp),
.S_AXI_BVALID(s00_axi_bvalid),
.S_AXI_BREADY(s00_axi_bready),
.S_AXI_ARADDR(s00_axi_araddr),
.S_AXI_ARPROT(s00_axi_arprot),
.S_AXI_ARVALID(s00_axi_arvalid),
.S_AXI_ARREADY(s00_axi_arready),
.S_AXI_RDATA(s00_axi_rdata),
.S_AXI_RRESP(s00_axi_rresp),
.S_AXI_RVALID(s00_axi_rvalid),
.S_AXI_RREADY(s00_axi_rready)
); // Add user logic here // User logic ends endmodule
ip核实现文件mygpio_v1_0_S00_AXI.v：
module mygpio_v1_0_S00_AXI #
(
// Users to add parameters here // User parameters ends
// Do not modify the parameters beyond this line // Width of S_AXI data bus
parameter integer C_S_AXI_DATA_WIDTH = 32,
// Width of S_AXI address bus
parameter integer C_S_AXI_ADDR_WIDTH = 4
)
(
// Users to add ports here
//*********************my code ****************************************
input wire [7:0] SW_In,
output wire [7:0] LED_Out,
// User ports ends
// Do not modify the ports beyond this line // Global Clock Signal
input wire S_AXI_ACLK,
// Global Reset Signal. This Signal is Active LOW
input wire S_AXI_ARESETN,
// Write address (issued by master, acceped by Slave)
input wire [C_S_AXI_ADDR_WIDTH-1 : 0] S_AXI_AWADDR,
// Write channel Protection type. This signal indicates the
// privilege and security level of the transaction, and whether
// the transaction is a data access or an instruction access.
input wire [2 : 0] S_AXI_AWPROT,
// Write address valid. This signal indicates that the master signaling
// valid write address and control information.
input wire S_AXI_AWVALID,
// Write address ready. This signal indicates that the slave is ready
// to accept an address and associated control signals.
output wire S_AXI_AWREADY,
// Write data (issued by master, acceped by Slave)
input wire [C_S_AXI_DATA_WIDTH-1 : 0] S_AXI_WDATA,
// Write strobes. This signal indicates which byte lanes hold
// valid data. There is one write strobe bit for each eight
// bits of the write data bus.
input wire [(C_S_AXI_DATA_WIDTH/8)-1 : 0] S_AXI_WSTRB,
// Write valid. This signal indicates that valid write
// data and strobes are available.
input wire S_AXI_WVALID,
// Write ready. This signal indicates that the slave
// can accept the write data.
output wire S_AXI_WREADY,
// Write response. This signal indicates the status
// of the write transaction.
output wire [1 : 0] S_AXI_BRESP,
// Write response valid. This signal indicates that the channel
// is signaling a valid write response.
output wire S_AXI_BVALID,
// Response ready. This signal indicates that the master
// can accept a write response.
input wire S_AXI_BREADY,
// Read address (issued by master, acceped by Slave)
input wire [C_S_AXI_ADDR_WIDTH-1 : 0] S_AXI_ARADDR,
// Protection type. This signal indicates the privilege
// and security level of the transaction, and whether the
// transaction is a data access or an instruction access.
input wire [2 : 0] S_AXI_ARPROT,
// Read address valid. This signal indicates that the channel
// is signaling valid read address and control information.
input wire S_AXI_ARVALID,
// Read address ready. This signal indicates that the slave is
// ready to accept an address and associated control signals.
output wire S_AXI_ARREADY,
// Read data (issued by slave)
output wire [C_S_AXI_DATA_WIDTH-1 : 0] S_AXI_RDATA,
// Read response. This signal indicates the status of the
// read transfer.
output wire [1 : 0] S_AXI_RRESP,
// Read valid. This signal indicates that the channel is
// signaling the required read data.
output wire S_AXI_RVALID,
// Read ready. This signal indicates that the master can
// accept the read data and response information.
input wire S_AXI_RREADY
); // AXI4LITE signals
reg [C_S_AXI_ADDR_WIDTH-1 : 0] axi_awaddr;
reg axi_awready;
reg axi_wready;
reg [1 : 0] axi_bresp;
reg axi_bvalid;
reg [C_S_AXI_ADDR_WIDTH-1 : 0] axi_araddr;
reg axi_arready;
reg [C_S_AXI_DATA_WIDTH-1 : 0] axi_rdata;
reg [1 : 0] axi_rresp;
reg axi_rvalid; // Example-specific design signals
// local parameter for addressing 32 bit / 64 bit C_S_AXI_DATA_WIDTH
// ADDR_LSB is used for addressing 32/64 bit registers/memories
// ADDR_LSB = 2 for 32 bits (n downto 2)
// ADDR_LSB = 3 for 64 bits (n downto 3)
localparam integer ADDR_LSB = (C_S_AXI_DATA_WIDTH/32) + 1;
localparam integer OPT_MEM_ADDR_BITS = 1;
//----------------------------------------------
//-- Signals for user logic register space example
//*********************my code ****************************************
wire [31:0] reg0_wire;
reg [31:0] SW_Reg0;
reg [31:0] SW_Reg1;
//------------------------------------------------
//-- Number of Slave Registers 4
reg [C_S_AXI_DATA_WIDTH-1:0] slv_reg0;
reg [C_S_AXI_DATA_WIDTH-1:0] slv_reg1;
reg [C_S_AXI_DATA_WIDTH-1:0] slv_reg2;
reg [C_S_AXI_DATA_WIDTH-1:0] slv_reg3;
wire slv_reg_rden;
wire slv_reg_wren;
reg [C_S_AXI_DATA_WIDTH-1:0] reg_data_out;
integer byte_index; // I/O Connections assignments assign S_AXI_AWREADY = axi_awready;
assign S_AXI_WREADY = axi_wready;
assign S_AXI_BRESP = axi_bresp;
assign S_AXI_BVALID = axi_bvalid;
assign S_AXI_ARREADY = axi_arready;
assign S_AXI_RDATA = axi_rdata;
assign S_AXI_RRESP = axi_rresp;
assign S_AXI_RVALID = axi_rvalid;
// Implement axi_awready generation
// axi_awready is asserted for one S_AXI_ACLK clock cycle when both
// S_AXI_AWVALID and S_AXI_WVALID are asserted. axi_awready is
// de-asserted when reset is low. always @( posedge S_AXI_ACLK )
begin
if ( S_AXI_ARESETN == 1'b0 )
begin
axi_awready <= 1'b0;
end
else
begin
if (~axi_awready && S_AXI_AWVALID && S_AXI_WVALID)
begin
// slave is ready to accept write address when
// there is a valid write address and write data
// on the write address and data bus. This design
// expects no outstanding transactions.
axi_awready <= 1'b1;
end
else
begin
axi_awready <= 1'b0;
end
end
end // Implement axi_awaddr latching
// This process is used to latch the address when both
// S_AXI_AWVALID and S_AXI_WVALID are valid. always @( posedge S_AXI_ACLK )
begin
if ( S_AXI_ARESETN == 1'b0 )
begin
axi_awaddr <= 0;
end
else
begin
if (~axi_awready && S_AXI_AWVALID && S_AXI_WVALID)
begin
// Write Address latching
axi_awaddr <= S_AXI_AWADDR;
end
end
end // Implement axi_wready generation
// axi_wready is asserted for one S_AXI_ACLK clock cycle when both
// S_AXI_AWVALID and S_AXI_WVALID are asserted. axi_wready is
// de-asserted when reset is low. always @( posedge S_AXI_ACLK )
begin
if ( S_AXI_ARESETN == 1'b0 )
begin
axi_wready <= 1'b0;
end
else
begin
if (~axi_wready && S_AXI_WVALID && S_AXI_AWVALID)
begin
// slave is ready to accept write data when
// there is a valid write address and write data
// on the write address and data bus. This design
// expects no outstanding transactions.
axi_wready <= 1'b1;
end
else
begin
axi_wready <= 1'b0;
end
end
end // Implement memory mapped register select and write logic generation
// The write data is accepted and written to memory mapped registers when
// axi_awready, S_AXI_WVALID, axi_wready and S_AXI_WVALID are asserted. Write strobes are used to
// select byte enables of slave registers while writing.
// These registers are cleared when reset (active low) is applied.
// Slave register write enable is asserted when valid address and data are available
// and the slave is ready to accept the write address and write data.
assign slv_reg_wren = axi_wready && S_AXI_WVALID && axi_awready && S_AXI_AWVALID; always @( posedge S_AXI_ACLK )
begin
if ( S_AXI_ARESETN == 1'b0 )
begin
// slv_reg0 <= 0;
slv_reg1 <= 0;
slv_reg2 <= 0;
slv_reg3 <= 0;
end
else begin
if (slv_reg_wren)
begin
case ( axi_awaddr[ADDR_LSB+OPT_MEM_ADDR_BITS:ADDR_LSB] )
//*********************my modify ****************************************
// 2'h0:
// for ( byte_index = 0; byte_index <= (C_S_AXI_DATA_WIDTH/8)-1; byte_index = byte_index+1 )
// if ( S_AXI_WSTRB[byte_index] == 1 ) begin
// Respective byte enables are asserted as per write strobes
// Slave register 0
// slv_reg0[(byte_index*8) +: 8] <= S_AXI_WDATA[(byte_index*8) +: 8];
// end
2'h1:
for ( byte_index = 0; byte_index <= (C_S_AXI_DATA_WIDTH/8)-1; byte_index = byte_index+1 )
if ( S_AXI_WSTRB[byte_index] == 1 ) begin
// Respective byte enables are asserted as per write strobes
// Slave register 1
slv_reg1[(byte_index*8) +: 8] <= S_AXI_WDATA[(byte_index*8) +: 8];
end
2'h2:
for ( byte_index = 0; byte_index <= (C_S_AXI_DATA_WIDTH/8)-1; byte_index = byte_index+1 )
if ( S_AXI_WSTRB[byte_index] == 1 ) begin
// Respective byte enables are asserted as per write strobes
// Slave register 2
slv_reg2[(byte_index*8) +: 8] <= S_AXI_WDATA[(byte_index*8) +: 8];
end
2'h3:
for ( byte_index = 0; byte_index <= (C_S_AXI_DATA_WIDTH/8)-1; byte_index = byte_index+1 )
if ( S_AXI_WSTRB[byte_index] == 1 ) begin
// Respective byte enables are asserted as per write strobes
// Slave register 3
slv_reg3[(byte_index*8) +: 8] <= S_AXI_WDATA[(byte_index*8) +: 8];
end
default : begin
slv_reg0 <= slv_reg0;
slv_reg1 <= slv_reg1;
slv_reg2 <= slv_reg2;
slv_reg3 <= slv_reg3;
end
endcase
end
end
end // Implement write response logic generation
// The write response and response valid signals are asserted by the slave
// when axi_wready, S_AXI_WVALID, axi_wready and S_AXI_WVALID are asserted.
// This marks the acceptance of address and indicates the status of
// write transaction. always @( posedge S_AXI_ACLK )
begin
if ( S_AXI_ARESETN == 1'b0 )
begin
axi_bvalid <= 0;
axi_bresp <= 2'b0;
end
else
begin
if (axi_awready && S_AXI_AWVALID && ~axi_bvalid && axi_wready && S_AXI_WVALID)
begin
// indicates a valid write response is available
axi_bvalid <= 1'b1;
axi_bresp <= 2'b0; // 'OKAY' response
end // work error responses in future
else
begin
if (S_AXI_BREADY && axi_bvalid)
//check if bready is asserted while bvalid is high)
//(there is a possibility that bready is always asserted high)
begin
axi_bvalid <= 1'b0;
end
end
end
end // Implement axi_arready generation
// axi_arready is asserted for one S_AXI_ACLK clock cycle when
// S_AXI_ARVALID is asserted. axi_awready is
// de-asserted when reset (active low) is asserted.
// The read address is also latched when S_AXI_ARVALID is
// asserted. axi_araddr is reset to zero on reset assertion. always @( posedge S_AXI_ACLK )
begin
if ( S_AXI_ARESETN == 1'b0 )
begin
axi_arready <= 1'b0;
axi_araddr <= 32'b0;
end
else
begin
if (~axi_arready && S_AXI_ARVALID)
begin
// indicates that the slave has acceped the valid read address
axi_arready <= 1'b1;
// Read address latching
axi_araddr <= S_AXI_ARADDR;
end
else
begin
axi_arready <= 1'b0;
end
end
end // Implement axi_arvalid generation
// axi_rvalid is asserted for one S_AXI_ACLK clock cycle when both
// S_AXI_ARVALID and axi_arready are asserted. The slave registers
// data are available on the axi_rdata bus at this instance. The
// assertion of axi_rvalid marks the validity of read data on the
// bus and axi_rresp indicates the status of read transaction.axi_rvalid
// is deasserted on reset (active low). axi_rresp and axi_rdata are
// cleared to zero on reset (active low).
always @( posedge S_AXI_ACLK )
begin
if ( S_AXI_ARESETN == 1'b0 )
begin
axi_rvalid <= 0;
axi_rresp <= 0;
end
else
begin
if (axi_arready && S_AXI_ARVALID && ~axi_rvalid)
begin
// Valid read data is available at the read data bus
axi_rvalid <= 1'b1;
axi_rresp <= 2'b0; // 'OKAY' response
end
else if (axi_rvalid && S_AXI_RREADY)
begin
// Read data is accepted by the master
axi_rvalid <= 1'b0;
end
end
end // Implement memory mapped register select and read logic generation
// Slave register read enable is asserted when valid address is available
// and the slave is ready to accept the read address.
assign slv_reg_rden = axi_arready & S_AXI_ARVALID & ~axi_rvalid;
always @(*)
begin
if ( S_AXI_ARESETN == 1'b0 )
begin
reg_data_out <= 0;
end
else
begin
// Address decoding for reading registers
case ( axi_araddr[ADDR_LSB+OPT_MEM_ADDR_BITS:ADDR_LSB] )
2'h0 : reg_data_out <= slv_reg0;
2'h1 : reg_data_out <= slv_reg1;
2'h2 : reg_data_out <= slv_reg2;
2'h3 : reg_data_out <= slv_reg3;
default : reg_data_out <= 0;
endcase
end
end // Output register or memory read data
always @( posedge S_AXI_ACLK )
begin
if ( S_AXI_ARESETN == 1'b0 )
begin
axi_rdata <= 0;
end
else
begin
// When there is a valid read address (S_AXI_ARVALID) with
// acceptance of read address by the slave (axi_arready),
// output the read dada
if (slv_reg_rden)
begin
axi_rdata <= reg_data_out; // register read data
end
end
end
//*********************my code ****************************************
// Add user logic here
led_ul U1(
.S_AXI_ACLK(S_AXI_ACLK),
.slv_reg_wren(slv_reg_wren),
.axi_awaddr(axi_awaddr[ADDR_LSB+OPT_MEM_ADDR_BITS:ADDR_LSB]),
.S_AXI_WDATA(S_AXI_WDATA),
.aresetn(S_AXI_ARESETN),
.LED(LED_Out)
); assign reg0_wire = slv_reg0; sw_ul U2(
.S_AXI_ACLK(S_AXI_ACLK),
.slv_reg_rden(slv_reg_rden),
.axi_araddr(axi_araddr[3:2]),
.aresetn(S_AXI_ARESETN),
.SW_In(SW_In),
.rdata(reg0_wire)
); // always @(slv_reg_rden or slv_reg0 or slv_reg1)
// begin
// case ( axi_araddr[ADDR_LSB+OPT_MEM_ADDR_BITS:ADDR_LSB] )
// 2'h0 : reg_data_out <= slv_reg0;
// 2'h1 : reg_data_out <= slv_reg1;
// default:reg_data_out <= 0;
// endcase
// end // User logic ends endmodule
在这个文件中，我注释了AXI总线在写数据时对于slv_reg0写的定义，因为在我们的用户代码中使用一条reg0_wire将slv_reg0连到了sw_ul子核中，并且在子核中对reg0定义写操作（即将sw的状态输出到slv_reg0)，然后另一段代码会将其放入reg_data_out，最后在slv_reg_rden线的输出为1时，它会进一步被送往axi_rdata，并通过数据总线S_AXI_RDATA输出。
ip核内包含的子文件sw_ul.v
module sw_ul(
input S_AXI_ACLK,
input slv_reg_rden,
input [1:0] axi_araddr,
input aresetn,
input [7:0] SW_In,
output reg [31:0] rdata
);
reg [31:0] SW_Reg0;
reg [31:0] SW_Reg1;
always @(posedge S_AXI_ACLK)
begin
if ( aresetn == 1'b0 )
begin
SW_Reg0 <= 0;
SW_Reg1 <= 0;
rdata <= 0;
end
else
begin
if(slv_reg_rden)
begin
if(axi_araddr == 2'h0)
begin
SW_Reg0 <= SW_In;
SW_Reg1 <= SW_Reg0;
rdata[7:0] <= SW_Reg1[7:0];
end
end end
end
endmodule
ip核内包含的子文件led_ul.v
module led_ul(
input S_AXI_ACLK,
input slv_reg_wren,
input [1:0] axi_awaddr,
input [31:0] S_AXI_WDATA,
input aresetn,
output reg [7:0] LED
); always @( posedge S_AXI_ACLK )
begin
if( aresetn == 1'b0 )
begin
LED <= 8'b10011001;
end
else
begin
if (slv_reg_wren && (axi_awaddr == 2'h1))
begin
LED <= S_AXI_WDATA[7:0];
end
// LED <= 8'b11111111;
// if (slv_reg_wren)
// begin
// case(axi_awaddr)
// 2'h1:
// begin
// LED <= S_AXI_WDATA[7:0];
// LED <= 8'b00000001;
// end
// 2'h0:
// begin
// LED <= 8'b00000000;
// end
// default:
// begin
// LED <= 8'b11111111;
// end
// endcase
// end
end
end endmodule
EDK中standalone程序：
#include <stdio.h>
#include "xparameters.h"
#include "xil_io.h"
#include "mygpio.h"
#include "platform.h" int main()
{
u32 inData = 0;
init_platform();
while(1)
{
inData = Xil_In32(XPAR_MYGPIO_0_S00_AXI_BASEADDR);
xil_printf("SW0 data is 0x%x\n\r",inData);
Xil_Out32(XPAR_MYGPIO_0_S00_AXI_BASEADDR+MYGPIO_S00_AXI_SLV_REG1_OFFSET,inData);
//inData = Xil_In32(XPAR_MYGPIO_0_S00_AXI_BASEADDR+1);
//xil_printf("SW1 data is 0x%x\n\r",inData);
//MYGPIO_mWriteReg(XPAR_MYGPIO_0_S00_AXI_BASEADDR,0,inData);
//sleep(1);
}
return 0;
}
刚开始一直都测试不成功，一直得不到ip核中axi_araddr等于1的状态（即写第一个slv_reg1)，后来看到了MYGPIO_S00_AXI_SLV_REG1_OFFSET=4，寄存器设置时设置的是32b，就是4Byte，灯只用到了其中最后的8bit，地址从0x43C00000开始，编号为1的寄存器地址应该是0x43C00004(存储器字长=1B)。（我们的ip核中，reg0用来存放sw读出的数据，而reg1用来从axi总线给led灯传送数据）。
参考文献：懒兔子教程