begin j_a <= input_a end;
时间: 2024-02-11 10:04:00 浏览: 22
这行代码是一个赋值语句,将 `input_a` 的值赋给 `j_a` 变量。然而,它需要包含在一个 `always` 块中才能正确地工作。在 Verilog 中,`always` 块用于指定某些代码在特定条件下执行的频率。例如,以下代码示例将 `j_a` 变量始终设置为 `input_a` 的值:
```
always @(input_a) begin
j_a <= input_a;
end
```
在这个例子中,`always` 块的条件是 `input_a`,这意味着只要 `input_a` 的值发生变化,`j_a` 就会被重新赋值为该值。
请注意,如果你使用的是 Verilog-2001 或更高版本,你可以使用 `always_comb` 替换 `always @(*)`,以便更明确地表示这是一个组合逻辑块。
```
always_comb begin
j_a <= input_a;
end
```
这样可以确保 `j_a` 始终与 `input_a` 的值同步。如果你需要更多关于 `always` 块的信息,请查阅 Verilog 的相关文档。
相关问题
请帮我纠正以下代码的错误:module pmod_oled_spi( input wire clk, input wire rst, input wire cs, input wire mosi, input wire sclk ); reg [7:0] data_out; reg [7:0] cnt; reg [1:0] state; parameter IDLE = 2'b00; parameter START = 2'b01; parameter WRITE = 2'b10; always @(posedge clk) begin if (rst) begin state <= IDLE; cnt <= 0; data_out <= 0; end else case (state) IDLE: begin if (cnt == 0) begin state <= START; cnt <= 1; end else cnt <= cnt; end START: begin if (cs == 1'b0) begin state <= WRITE; cnt <= 1; end else cnt <= cnt; end WRITE: begin if (cnt < 9) begin mosi <= data_out[7-cnt]; sclk <= 1'b0; cnt <= cnt + 1; end else begin mosi <= 1'b0; sclk <= 1'b1; state <= IDLE; cnt <= 0; end end default: cnt <= 0; endcase end always @(posedge clk) begin if (rst) begin data_out <= 0; end else if (state == WRITE) begin data_out <= data_out << 1 | 1'b0; // TODO: 根据OLED通信协议修改 end end endmodule
在这个代码中,有一个错误是在 always @(posedge clk) 的过程块中同时对 data_out 进行了赋值,这个赋值语句是冲突的。因为过程块中的语句是并行执行的,如果同时对 data_out 进行赋值,那么它的值会变得不可预测。下面是纠正后的代码:
```verilog
module pmod_oled_spi(
input wire clk,
input wire rst,
input wire cs,
input wire mosi,
input wire sclk
);
reg [7:0] data_out;
reg [7:0] cnt;
reg [1:0] state;
parameter IDLE = 2'b00;
parameter START = 2'b01;
parameter WRITE = 2'b10;
always @(posedge clk) begin
if (rst) begin
state <= IDLE;
cnt <= 0;
data_out <= 0;
end else case (state)
IDLE: begin
if (cnt == 0) begin
state <= START;
cnt <= 1;
end else cnt <= cnt;
end
START: begin
if (cs == 1'b0) begin
state <= WRITE;
cnt <= 1;
end else cnt <= cnt;
end
WRITE: begin
if (cnt < 9) begin
mosi <= data_out[7-cnt];
sclk <= 1'b0;
cnt <= cnt + 1;
end else begin
mosi <= 1'b0;
sclk <= 1'b1;
state <= IDLE;
cnt <= 0;
end
end
default: cnt <= 0;
endcase
end
always @(posedge clk) begin
if (rst) begin
data_out <= 0;
end else if (state == WRITE && cnt == 0) begin
data_out <= data_out << 1 | 1'b0; // TODO: 根据OLED通信协议修改
end else begin
data_out <= data_out;
end
end
endmodule
```
在修改后的代码中,我们将对 data_out 的赋值从第一个过程块中移除,并将它放在第二个过程块中,这样就不会出现并行赋值的问题了。
module ram_write ( input wire sys_clk , input wire sys_rst_n , input wire cnt_rcd, input wire [7:0] seg_cnt_data0 , input wire [7:0] seg_cnt_data1 , input wire [7:0] seg_cnt_data2 , input wire [7:0] seg_cnt_data3 , input wire [7:0] seg_cnt_data4 , input wire [7:0] seg_cnt_data5 , output reg [4:0] addr, output reg write_en , output reg [7:0] data_in ); reg [3:0] bite ; reg [3:0] times=0; always @(posedge sys_clk or negedge sys_rst_n) begin if (!sys_rst_n) begin write_en <= 1'b0 ; end else if (cnt_rcd) begin write_en <= 1'b1; times <= times + 1; end else begin write_en <= 1'b0; end end always @(posedge sys_clk or negedge sys_rst_n) if(!sys_rst_n) begin bite <='d0; addr <='d0; data_in <='d0; end else if(write_en) begin case(bite) 'd0: begin addr <= 2'd0+6times ; data_in<= seg_cnt_data0 ; bite<=bite + 1 ; end 'd1: begin addr <= 2'd1+6times ; data_in<= seg_cnt_data1; bite<=bite + 1 ; end 'd2: begin addr <= 2'd2+6times ; data_in<= seg_cnt_data2 ; bite<=bite + 1 ; end 'd3: begin addr <= 2'd3+6times ; data_in<= seg_cnt_data3 ; bite<=bite + 1 ; end 'd4: begin addr <= 2'd4+6times ; data_in<= seg_cnt_data4 ; bite<=bite + 1 ; end 'd5: begin addr <= 2'd5+6times ; data_in<= seg_cnt_data5 ; bite<=bite + 1 ; end default: ; endcase end endmodule修改代码
根据您提供的代码,我发现在更新 `addr` 时,使用的是 `6times`,这里应该是 `6*times`,需要在乘法符号前面加上 `*`,以正确计算地址。请尝试修改如下代码:
```
module ram_write (
input wire sys_clk,
input wire sys_rst_n,
input wire cnt_rcd,
input wire [7:0] seg_cnt_data0,
input wire [7:0] seg_cnt_data1,
input wire [7:0] seg_cnt_data2,
input wire [7:0] seg_cnt_data3,
input wire [7:0] seg_cnt_data4,
input wire [7:0] seg_cnt_data5,
output reg [4:0] addr,
output reg write_en,
output reg [7:0] data_in
);
reg [3:0] bite;
reg [3:0] times = 0;
always @(posedge sys_clk or negedge sys_rst_n) begin
if (!sys_rst_n) begin
write_en <= 1'b0;
end else if (cnt_rcd) begin
write_en <= 1'b1;
times <= times + 1;
end else begin
write_en <= 1'b0;
end
end
always @(posedge sys_clk or negedge sys_rst_n) begin
if (!sys_rst_n) begin
bite <= 'd0;
addr <= 'd0;
data_in <= 'd0;
end else if (write_en) begin
case (bite)
'd0: begin
addr <= 2'd0 + 6 * times;
data_in <= seg_cnt_data0;
bite <= bite + 1;
end
'd1: begin
addr <= 2'd1 + 6 * times;
data_in <= seg_cnt_data1;
bite <= bite + 1;
end
'd2: begin
addr <= 2'd2 + 6 * times;
data_in <= seg_cnt_data2;
bite <= bite + 1;
end
'd3: begin
addr <= 2'd3 + 6 * times;
data_in <= seg_cnt_data3;
bite <= bite + 1;
end
'd4: begin
addr <= 2'd4 + 6 * times;
data_in <= seg_cnt_data4;
bite <= bite + 1;
end
'd5: begin
addr <= 2'd5 + 6 * times;
data_in <= seg_cnt_data5;
bite <= bite + 1;
end
default: ;
endcase
end
end
endmodule
```
请尝试使用上述代码,看看问题是否得到解决。