axi slave如何处理outstanding
时间: 2023-05-17 12:06:47 浏览: 371
Axi Slave 处理 outstanding 的方式是通过使用 AXI 协议中的 WREADY 信号来通知 Master,表示 Slave 已经准备好接收下一个数据传输。如果 Slave 没有准备好接收下一个数据传输,它可以将 WREADY 信号保持低电平,这将导致 Master 在 AXI 协议中等待,直到 Slave 准备好接收下一个数据传输。
相关问题
verilog AXI slave with outstanding
An AXI slave with outstanding transactions can be implemented in Verilog by using a state machine to manage the response to incoming transactions. The state machine can keep track of the number of outstanding transactions and respond accordingly. Here is an example implementation:
```
module axi_slave_outstanding(
input aclk,
input aresetn,
input awvalid,
input [31:0] awaddr,
input [2:0] awprot,
input awcache,
input awburst,
input [3:0] awlen,
input arvalid,
input [31:0] araddr,
input [2:0] arprot,
input arcache,
input arburst,
input [3:0] arlen,
input wvalid,
input [31:0] wdata,
input [3:0] wstrb,
input wlast,
output bvalid,
output rvalid,
output [1:0] rresp,
output [31:0] rdata,
output rlast
);
reg [1:0] state;
reg [31:0] mem[0:1023];
reg [3:0] arcount;
reg [3:0] awcount;
// Reset state machine and counters on reset
always @(posedge aclk) begin
if (!aresetn) begin
state <= 2'b00;
arcount <= 4'b0000;
awcount <= 4'b0000;
end
end
// State machine
always @(posedge aclk) begin
case (state)
// Idle state
2'b00: begin
if (awvalid) begin
state <= 2'b01;
awcount <= awlen;
end else if (arvalid) begin
state <= 2'b10;
arcount <= arlen;
end
end
// Write data state
2'b01: begin
if (wvalid) begin
mem[awaddr] <= wdata;
awaddr <= awaddr + 1;
awcount <= awcount - 1;
if (wlast) begin
bvalid <= 1'b1;
state <= 2'b00;
end
end
end
// Read data state
2'b10: begin
if (rcount == 4'b0000) begin
rvalid <= 1'b1;
rdata <= mem[araddr];
end
araddr <= araddr + 1;
arcount <= arcount - 1;
if (arcount == 4'b0000) begin
rlast <= 1'b1;
rvalid <= 1'b0;
state <= 2'b00;
end
end
// Error state
default: begin
state <= 2'b00;
end
endcase
end
endmodule
```
In this implementation, the state machine has three states: idle, write data, and read data. When an AXI write transaction is received, the state machine transitions to the write data state and writes the incoming data to memory. It also keeps track of the number of outstanding write transactions using the `awcount` counter. When an AXI read transaction is received, the state machine transitions to the read data state and reads the requested data from memory. It also keeps track of the number of outstanding read transactions using the `arcount` counter.
The `bvalid`, `rvalid`, `rdata`, and `rlast` outputs are used to signal the completion of the AXI transactions to the master. The `bvalid` output is set to 1 when a write response is ready, and the `rvalid` output is set to 1 when a read response is ready. The `rdata` output contains the read data, and the `rlast` output signals the end of a read transaction.
This implementation assumes a single master and a single slave, and does not support burst transactions or interleaved transactions. It also does not support any AXI extensions beyond the basic read and write transactions.
AXI slave代码
你想了解关于 AXI slave 的代码,这是一种常用的总线协议,用于在嵌入式系统中实现高速数据传输。以下是一个简单的 AXI slave 代码示例,供你参考:
```c
#include <stdio.h>
#include <stdint.h>
#define AXI_SLAVE_BASE_ADDR 0x40000000
// AXI slave读取数据的函数
uint32_t axi_slave_read(uint32_t addr) {
// 计算相对地址
uint32_t offset = addr - AXI_SLAVE_BASE_ADDR;
// 读取数据并返回
uint32_t data = *((volatile uint32_t *)(AXI_SLAVE_BASE_ADDR + offset));
return data;
}
// AXI slave写入数据的函数
void axi_slave_write(uint32_t addr, uint32_t data) {
// 计算相对地址
uint32_t offset = addr - AXI_SLAVE_BASE_ADDR;
// 写入数据
*((volatile uint32_t *)(AXI_SLAVE_BASE_ADDR + offset)) = data;
}
int main() {
// 读取示例
uint32_t readData = axi_slave_read(0x40000004);
printf("Read Data: 0x%08X\n", readData);
// 写入示例
axi_slave_write(0x40000008, 0xABCD1234);
printf("Write Data: 0xABCD1234\n");
return 0;
}
```
在这个示例中,我们假设 AXI slave 的基地址为 0x40000000。`axi_slave_read` 函数用于从指定地址读取数据,`axi_slave_write` 函数用于向指定地址写入数据。你可以根据实际需求修改基地址和具体的读写逻辑。
请注意,这只是一个简单的示例,实际应用中可能需要根据具体的需求进行更加复杂的实现。同时,确保在使用 AXI slave 时遵循相应的规范和协议。