verilog实现i2c的master
时间: 2023-07-27 12:08:21 浏览: 47
要在Verilog中实现I2C总线的主设备(Master),你需要编写一个模块来控制I2C总线的时序和通信协议。以下是一个简单的Verilog代码示例,展示了如何实现I2C主设备的基本功能:
```verilog
module I2C_Master(
input wire clk,
input wire rst,
inout wire sda,
inout wire scl,
input wire start,
input wire stop,
input wire [7:0] data_in,
output wire [7:0] data_out,
output reg ack
);
reg [7:0] data;
reg [2:0] state;
reg [3:0] bit_counter;
reg sda_out;
parameter IDLE = 3'b000;
parameter START = 3'b001;
parameter SEND_ADDRESS = 3'b010;
parameter SEND_DATA = 3'b011;
parameter RECEIVE_ACK = 3'b100;
parameter RECEIVE_DATA = 3'b101;
parameter SEND_STOP = 3'b110;
always @(posedge clk or posedge rst) begin
if (rst) begin
state <= IDLE;
bit_counter <= 0;
data <= 0;
sda_out <= 1;
ack <= 0;
end else begin
case (state)
IDLE:
if (start)
state <= START;
START:
begin
sda_out <= 0;
state <= SEND_ADDRESS;
bit_counter <= 7;
end
SEND_ADDRESS:
begin
sda_out <= data[bit_counter];
if (bit_counter == 0)
state <= RECEIVE_ACK;
else
bit_counter <= bit_counter - 1;
end
RECEIVE_ACK:
begin
sda_out <= 1;
if (sda == 0)
ack <= 1;
else
ack <= 0;
state <= SEND_DATA;
bit_counter <= 7;
end
SEND_DATA:
begin
sda_out <= data[bit_counter];
if (bit_counter == 0)
state <= RECEIVE_ACK;
else
bit_counter <= bit_counter - 1;
end
RECEIVE_DATA:
begin
data_out <= sda;
if (bit_counter == 0)
state <= SEND_STOP;
else
bit_counter <= bit_counter - 1;
end
SEND_STOP:
begin
sda_out <= 0;
state <= IDLE;
end
endcase
end
end
assign sda = sda_out;
endmodule
```
这个例子中的I2C主设备模块包含了时钟(clk)和复位(rst)输入,以及I2C总线的数据线(sda)和时钟线(scl)作为双向的输入/输出端口。它还包括用于启动(start)、停止(stop)、发送数据(data_in)和接收数据(data_out)的输入信号。
主设备模块内部使用状态机(state machine)实现了I2C通信协议。状态机跟踪I2C通信的不同阶段,并根据每个阶段的要求设置数据线和时序。
请注意,这只是一个简单的示例,可能需要根据具体的应用场景进行修改和扩展。完成后,你可以根据需要将该模块与其他模块进行连接,以实现完整的I2C主设备功能。