CAN通信控制的FIFO是什么示范代码

2018-12-24 10:30:33 1758 CAN通信 CAN

0 为实现数据的快速交换，使用了 FIFO，代码如下： assign write_length_info = (~wr) & wr_q; //延迟写信号 always @ (posedge clk or posedge rst) begin if (rst) wr_q <= 0; else if (reset_mode) wr_q <=#Tp 0; else wr_q <=#Tp wr; end // 数据长度计数器 always @ (posedge clk or posedge rst) begin if (rst) len_cnt <= 0; else if (reset_mode \| write_length_info) len_cnt <=#Tp 1'b0; else if (wr & (~fifo_full)) len_cnt <=#Tp len_cnt + 1'b1; end // 写信息指针 always @ (posedge clk or posedge rst) begin if (rst) wr_info_pointer <= 0; else if (reset_mode) wr_info_pointer <=#Tp 0; else if (write_length_info & (~info_full)) wr_info_pointer <=#Tp wr_info_pointer + 1'b1; end //读信息指针 always @ (posedge clk or posedge rst) begin if (rst) rd_info_pointer <= 0; else if (reset_mode) rd_info_pointer <=#Tp 0; else if (release_buffer & (~fifo_empty)) rd_info_pointer <=#Tp rd_info_pointer + 1'b1; end // 读指针 always @ (posedge clk or posedge rst) begin if (rst) rd_pointer <= 0; else if (release_buffer & (~fifo_empty)) rd_pointer <=#Tp rd_pointer + length_info; else if (reset_mode) rd_pointer <=#Tp 0; end // 写指针 always @ (posedge clk or posedge rst) begin if (rst) wr_pointer <= 0; else if (wr & (~fifo_full)) wr_pointer <=#Tp wr_pointer + 1'b1; else if (reset_mode) wr_pointer <=#Tp 0; end //锁存 always @ (posedge clk or posedge rst) begin if (rst) latch_overrun <= 0; else if (reset_mode \| write_length_info) latch_overrun <=#Tp 0; else if (wr & fifo_full) latch_overrun <=#Tp 1'b1; end //统计在 FIFO 中的数据 always @ (posedge clk or posedge rst) begin if (rst) fifo_cnt <= 0; else if (wr & (~release_buffer) & (~fifo_full)) fifo_cnt <=#Tp fifo_cnt + 1'b1; else if ((~wr) & release_buffer & (~fifo_empty)) fifo_cnt <=#Tp fifo_cnt - length_info; else if (wr & release_buffer & (~fifo_full) & (~fifo_empty)) fifo_cnt <=#Tp fifo_cnt - length_info + 1'b1; else if (reset_mode) fifo_cnt <=#Tp 0; end assign fifo_full = fifo_cnt == 64; assign fifo_empty = fifo_cnt == 0; //统计在 length_fifo 和 overrun_info fifo 中的数据 always @ (posedge clk or posedge rst) begin if (rst) info_cnt <= 0; else if (write_length_info ^ release_buffer) begin if (release_buffer & (~info_empty)) info_cnt <=#Tp info_cnt - 1'b1; else if (write_length_info & (~info_full)) info_cnt <=#Tp info_cnt + 1'b1; end end assign info_full = info_cnt == 64; assign info_empty = info_cnt == 0; //选择用来读数据的 FIFO 的地址 always @ (extended_mode or rd_pointer or addr) begin if (extended_mode) // extended mode begin read_address <= rd_pointer + (addr - 8'd16); end else // normal mode begin read_address <= rd_pointer + (addr - 8'd20); end end always @ (posedge clk) begin if (wr & (~fifo_full)) fifo[wr_pointer] <=#Tp data_in; end //从 FIFO 中读数据 assign data_out = fifo[read_address]; //写到 length_fifo always @ (posedge clk) begin if (write_length_info & (~info_full)) length_fifo[wr_info_pointer] <=#Tp len_cnt; end // 读 length_fifo 中的数据 assign length_info = length_fifo[rd_info_pointer]; // overrun_info always @ (posedge clk) begin if (write_length_info & (~info_full)) overrun_info[wr_info_pointer] <=#Tp latch_overrun \| (wr & fifo_full); end // 读取 overrun assign overrun = overrun_info[rd_info_pointer]; 复制代码 0
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