fifo问题急需求解
本帖最后由 fpgaw 于 2011-7-30 13:32 编辑自己写了个fifo程序！写入数据的速度快于读出数据的速度！我想将流水灯的数据写入fifo（速度快），然后每一秒读出一个数据，但是现象却不对，开始的时候流水灯正常，一个一个的亮，但是一会就不行了，就是隔一个亮一个了！不知道是怎么回事？求解！
写数据程序：
module write_module
(
clk,
rst_n,
full,
led_data,
write_en
);
input clk;
input rst_n;
input full;
output write_en;
output led_data;
reg write_en;
always @ ( posedge clk or negedge rst_n )
if( !rst_n ) write_en <= 1'b0;
else if( !full ) write_en <= 1'b1;
else write_en <= 1'b0;
reg led_data;
reg state;
always @ ( posedge clk or negedge rst_n )
begin
if( !rst_n ) begin
state <= 4'd0;
led_data <= 8'h00;
end
else if( !full )
case( state )
4'd0: beginled_data <= 8'h01; state <= state + 1'b1; end
4'd1: beginled_data <= 8'h02; state <= state + 1'b1; end
4'd2: beginled_data <= 8'h04; state <= state + 1'b1; end
4'd3: beginled_data <= 8'h08; state <= state + 1'b1; end
4'd4: beginled_data <= 8'h10; state <= state + 1'b1; end
4'd5: beginled_data <= 8'h20; state <= state + 1'b1; end
4'd6: beginled_data <= 8'h40; state <= state + 1'b1; end
4'd7: beginled_data <= 8'h80; state <= 4'd0; end
endcase
end
endmodule
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