tinyriscv/rtl/perips/gpio.v

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/*
Copyright 2020 Blue Liang, liangkangnan@163.com
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
// GPIO模块
module gpio(
input wire clk,
input wire rst,
input wire we_i,
input wire req_i,
input wire[31:0] addr_i,
input wire[31:0] data_i,
output reg[31:0] data_o,
output reg ack_o,
input wire[1:0] io_pin_i,
output wire[31:0] reg_ctrl,
output wire[31:0] reg_data
);
// GPIO控制寄存器
localparam GPIO_CTRL = 4'h0;
// GPIO数据寄存器
localparam GPIO_DATA = 4'h4;
// 每2位控制1个IO的模式最多支持16个IO
// 0: 高阻1输出2输入
reg[31:0] gpio_ctrl;
// 输入输出数据
reg[31:0] gpio_data;
assign reg_ctrl = gpio_ctrl;
assign reg_data = gpio_data;
// 写寄存器
always @ (posedge clk) begin
if (rst == 1'b0) begin
gpio_data <= 32'h0;
gpio_ctrl <= 32'h0;
end else begin
if (we_i == 1'b1) begin
case (addr_i[3:0])
GPIO_CTRL: begin
gpio_ctrl <= data_i;
end
GPIO_DATA: begin
gpio_data <= data_i;
end
endcase
end else begin
if (gpio_ctrl[1:0] == 2'b10) begin
gpio_data[0] <= io_pin_i[0];
end
if (gpio_ctrl[3:2] == 2'b10) begin
gpio_data[1] <= io_pin_i[1];
end
end
end
end
// 读寄存器
always @ (*) begin
if (rst == 1'b0) begin
data_o = 32'h0;
end else begin
case (addr_i[3:0])
GPIO_CTRL: begin
data_o = gpio_ctrl;
end
GPIO_DATA: begin
data_o = gpio_data;
end
default: begin
data_o = 32'h0;
end
endcase
end
end
endmodule