Altera DDR2 IP核学习总结3-----------DDR2 IP核的使用

Posted 2022-01-02 librarian

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技术图片

根据上一篇生成的IP核，例化之后如上图，Local开头的数据是用户侧数据，其他数据暂时不用纠结，不用管。

技术图片

这些是需要关注的信号，但是初学阶段很难对这些信号形成具体的概念，这里参考明德扬的代码进行二次封装。

module ddr2_intf(
clk_in ,
clk_out ,
rst_n ,
local_address ,
local_write_req ,
local_read_req ,
local_wdata ,
local_ready ,
local_rdata ,
local_rdata_valid,
local_init_done ,
local_burstbegin ,
user_wdata ,
user_wdata_en ,
user_waddr ,
user_raddr ,
user_rdata_en ,
user_rdata ,
user_rdata_vld ,
user_wdata_rdy ,
user_rdata_rdy
);
parameter ADDR_W = 23 ;
parameter DDR_DATA_W = 32 ;
parameter BURST = 2 ;
parameter USE_DATA_W = DDR_DATA_W * BURST;
parameter FIFO_W = USE_DATA_W + ADDR_W;
input clk_in ;
input rst_n ;
input clk_out ;
input local_ready ;
input [DDR_DATA_W-1:0] local_rdata ;
input local_rdata_valid;
input local_init_done ;
input [USE_DATA_W-1:0] user_wdata ;
input user_wdata_en ;
input [ADDR_W-1:0] user_waddr ;
input [ADDR_W-1:0] user_raddr ;
input user_rdata_en ;
output [ADDR_W-1:0] local_address ;
output local_write_req ;
output local_read_req ;
output [DDR_DATA_W-1:0] local_wdata ;
output local_burstbegin ;
output [USE_DATA_W-1:0] user_rdata ;
output user_rdata_vld ;
output user_wdata_rdy ;
output user_rdata_rdy ;
reg [USE_DATA_W-1:0] user_rdata ;
reg user_rdata_vld ;
reg user_wdata_rdy ;
reg user_rdata_rdy ;
wire [ADDR_W-1:0] local_address ;
wire local_write_req ;
wire local_read_req ;
wire [DDR_DATA_W-1:0] local_wdata ;
wire local_burstbegin ;
wire [FIFO_W-1:0] wfifo_wdata ;
wire wfifo_wrreq ;
wire wfifo_empty ;
wire wfifo_rdreq ;
wire [FIFO_W-1:0] wfifo_q ;
wire [ 5:0] wfifo_usedw ;
wire [ADDR_W-1:0] rfifo_wdata ;
wire rfifo_wrreq ;
wire rfifo_empty ;
wire rfifo_rdreq ;
wire [ADDR_W-1:0] rfifo_q ;
wire [ 5:0] rfifo_usedw ;
reg [FIFO_W :0] ififo_wdata ;
reg ififo_wrreq ;
wire ififo_empty ;
wire ififo_rdreq ;
wire [FIFO_W :0] ififo_q ;
wire [ 5:0] ififo_usedw ;
wire ififo_rdy ;
reg [USE_DATA_W-1:0] gfifo_wdata ;
reg gfifo_wrreq ;
wire gfifo_empty ;
wire gfifo_rdreq ;
wire [USE_DATA_W-1:0] gfifo_q ;
wire [ 5:0] gfifo_usedw ;
reg [ 1:0] cnt0 ;
wire add_cnt0 ;
wire end_cnt0 ;
reg [ 2:0] x ;
reg [ 3:0] cnt1 ;
wire add_cnt1 ;
wire end_cnt1 ;
fifo_ahead_sys #(.DATA_W(FIFO_W),.DEPT_W(64)) u_wfifo(
.aclr (~rst_n ),
.clock (clk_in ),
.data (wfifo_wdata ),
.rdreq (wfifo_rdreq ),
.wrreq (wfifo_wrreq ),
.empty (wfifo_empty ),
.q (wfifo_q ),
.usedw (wfifo_usedw )
);
fifo_ahead_sys #(.DATA_W(ADDR_W),.DEPT_W(64)) u_rfifo(
.aclr (~rst_n ),
.clock (clk_in ),
.data (rfifo_wdata ),
.rdreq (rfifo_rdreq ),
.wrreq (rfifo_wrreq ),
.empty (rfifo_empty ),
.q (rfifo_q ),
.usedw (rfifo_usedw )
);
fifo_ahead_asy #(.DATA_W(FIFO_W+1),.DEPT_W(64)) u_ififo(
.aclr (~rst_n ),
.data (ififo_wdata ),
.rdclk (clk_out ),
.rdreq (ififo_rdreq ),
.wrclk (clk_in ),
.wrreq (ififo_wrreq ),
.q (ififo_q ),
.rdempty (ififo_empty ),
.wrusedw (ififo_usedw )
);
assign wfifo_wdata = user_waddr,user_wdata;
assign wfifo_wrreq = user_wdata_en ;
assign wfifo_rdreq = ififo_rdy && wfifo_empty==0 && rfifo_empty==1;
assign rfifo_wdata = user_raddr ;
assign rfifo_wrreq = user_rdata_en ;
assign rfifo_rdreq = ififo_rdy && rfifo_empty==0;
always @(posedge clk_in or negedge rst_n)begin
if(rst_n==1‘b0)begin
ififo_wdata <= 0;
end
else if(wfifo_rdreq) begin
ififo_wdata <= 1‘b1,wfifo_q;
end
else if(rfifo_rdreq)begin
ififo_wdata <= 1‘b0,rfifo_q,USE_DATA_W1‘b0;
end
end
always @(posedge clk_in or negedge rst_n)begin
if(rst_n==1‘b0)begin
ififo_wrreq <= 0;
end
else begin
ififo_wrreq <= wfifo_rdreq || rfifo_rdreq;
end
end
assign ififo_rdy = ififo_usedw<40;
always @(posedge clk_in or negedge rst_n)begin
if(rst_n==1‘b0)begin
user_wdata_rdy <= 0;
end
else begin
user_wdata_rdy <= wfifo_usedw<40;
end
end
always @(posedge clk_in or negedge rst_n)begin
if(rst_n==1‘b0)begin
user_rdata_rdy <= 0;
end
else begin
user_rdata_rdy <= rfifo_usedw<40;
end
end
wire local_read_req_tmp;
assign local_wdata = ififo_q[USE_DATA_W-DDR_DATA_W*cnt0-1 -:DDR_DATA_W];
assign local_address = ififo_q[FIFO_W-1 -:ADDR_W];
assign local_write_req = ififo_q[FIFO_W] && ififo_empty==0 && local_init_done;
assign local_read_req_tmp = ififo_q[FIFO_W]==0 && ififo_empty==0 && local_init_done;
assign local_read_req = local_read_req_tmp && cnt0==1-1;
assign local_burstbegin= add_cnt0 && cnt0==1-1;
assign ififo_rdreq = end_cnt0;
reg ififo_q_ff0;
always @(posedge clk_out or negedge rst_n)begin
if(rst_n==1‘b0)begin
ififo_q_ff0<=0;
end
else begin
ififo_q_ff0<=ififo_q[FIFO_W];
end
end
always @(posedge clk_out or negedge rst_n)begin
if(!rst_n)begin
cnt0 <= 0;
end
else if(add_cnt0)begin
if(end_cnt0)
cnt0 <= 0;
else
cnt0 <= cnt0 + 1;
end
end
assign add_cnt0 = (local_write_req||local_read_req_tmp)&&local_ready;
assign end_cnt0 = add_cnt0 && cnt0==2-1;
always @(posedge clk_out or negedge rst_n)begin
if(!rst_n)begin
cnt1 <= 0;
end
else if(add_cnt1)begin
if(end_cnt1)
cnt1 <= 0;
else
cnt1 <= cnt1 + 1;
end
end
assign add_cnt1 = local_rdata_valid;
assign end_cnt1 = add_cnt1 && cnt1==BURST-1 ;
always @(posedge clk_out or negedge rst_n)begin
if(rst_n==1‘b0)begin
gfifo_wrreq <= 0;
end
else begin
gfifo_wrreq <= end_cnt1;
end
end
always @(posedge clk_out or negedge rst_n)begin
if(rst_n==1‘b0)begin
gfifo_wdata <= 0;
end
else if(add_cnt1)begin
gfifo_wdata[USE_DATA_W - DDR_DATA_W*cnt1 -1 -:DDR_DATA_W] <= local_rdata;
end
end
fifo_ahead_asy #(.DATA_W(USE_DATA_W),.DEPT_W(64)) u_gfifo(
.aclr (~rst_n ),
.data (gfifo_wdata ),
.rdclk (clk_in ),
.rdreq (gfifo_rdreq ),
.wrclk (clk_out ),
.wrreq (gfifo_wrreq ),
.q (gfifo_q ),
.rdempty (gfifo_empty ),
.wrusedw (gfifo_usedw )
);
assign gfifo_rdreq = gfifo_empty==0;
always @(posedge clk_in or negedge rst_n)begin
if(rst_n==1‘b0)begin
user_rdata <= 0;
end
else begin
user_rdata <= gfifo_q;
end
end
always @(posedge clk_in or negedge rst_n)begin
if(rst_n==1‘b0)begin
user_rdata_vld <= 0;
end
else begin
user_rdata_vld <= gfifo_rdreq;
end
end
endmodule