哪个网站有学做内帐的视频,网站建设与管理好处,学网站建设需要什么软件有哪些,模板站怎么改成营销型网站在FPGA中#xff0c;大规模数据的存储常常会用到DDR。为了方便用户使用#xff0c;Xilinx提供了DDR MIG IP核#xff0c;用户能够通过AXI接口进行DDR的读写访问#xff0c;然而MIG内部自动实现了许多环节#xff0c;不利于用户深入理解DDR的底层逻辑。
本文以美光(Micro…在FPGA中大规模数据的存储常常会用到DDR。为了方便用户使用Xilinx提供了DDR MIG IP核用户能够通过AXI接口进行DDR的读写访问然而MIG内部自动实现了许多环节不利于用户深入理解DDR的底层逻辑。
本文以美光(Micron公司生产的DDR3芯片MT41J512M8RH-093为例说明DDR芯片的操作过程。
该芯片的datasheet可以从厂商官网下载得到https://www.micron.com/-/media/client/global/documents/products/data-sheet/dram/ddr3/4gb_ddr3l.pdf?rev305217e2f9bd4ef48d7c6f353dfc064c这个datasheet包含了Micron公司多款DDR芯片这里MT41J512M8RH-093芯片对应数据位宽×8总容量4G512M×8频率2133-093的产品在表格中需要注意区分不同产品在时序参数上会有所区别。
DDR芯片的使用关键在于令接口的信号变化满足时序要求在初始化过程中主要关注下面几个时序参数来自P33 Table 9: Timing Parameters Used for IDD Measurements – Clock Units与P96 Table 59: Electrical Characteristics and AC Operating Conditions for Speed Extensions (Continued)
* CK(MIN) 0.938 ns
* CL 14 CK
* RCD(MIN) 14 CK
* RC(MIN) 50 CK
* RAS(MIN) 36 CK
* RP(MIN) 14 CK
* FAW 27 CK
* RRD 6 CK
* RFC 279CK
* XPR max(5CK, RFC10ns)
* MRD 4 CK
* MOD max(12 CK, 15ns)
* ZQinit max(512nCK, 640ns)
* DLLK 512 CK从datasheet的P12页的Fig2. Simplified State Diagram可以看到DDR3芯片在上电Power applied后需要经过一系列的初始化步骤主要包含三个部分Reset Procedure、Initialization、ZQ Calibration之后进入正常工作状态idle。
上图中Command由多个信号的变化构成在初始化过程主要用到以下几个指令。来自P118 Table 70: Truth Table – Command
* COMMAND | NOP | MRS_1 | MRS_2 | MRS_3 | MRS_4 | ZQCL
* ddr_cke | 1 1 | 1 1 | 1 1 | 1 1 | 1 1 | 1 1
* ddr_dqs_en | 0 | 0 | 0 | 0 | 0 | 0
* ddr_dq_en | 0 | 0 | 0 | 0 | 0 | 0
* ddr_cs_n | 0 | 0 | 0 | 0 | 0 | 0
* ddr_ras_n | 1 | 0 | 0 | 0 | 0 | 1
* ddr_cas_n | 1 | 0 | 0 | 0 | 0 | 1
* ddr_we_n | 1 | 0 | 0 | 0 | 0 | 0
* ddr_ba | vvv | 010 | 011 | 001 | 000 | 000
* ddr_addr | vvv | 28 | 00 | 44 | 124 | a[10]1
* ddr_odt | 0 | 0 | 0 | 0 | 0 | 0 这里将时钟周期取为最小时钟周期0.938ns对应时钟频率1066.099MHz。经过计算Initialization阶段每条指令执行后的等待时间均不超过1us因此这里将Initialization阶段每条指令执行后的等待时间均简化1us最终得到的DDR3初始化代码如下
timescale 1ns / 1ps
//
// Company:
// Engineer: wjh776a68
//
// Create Date: 01/05/2024 09:45:15 AM
// Design Name: micron_ddr
// Module Name: micron_ddr_init
// Project Name: micron_ddr
// Target Devices: vu9p
// Tool Versions: 2017.4
// Description:
//
// Dependencies:
//
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
//
//// ddr3 x8 4Gb MT41J512M8RH-093
/****************************
* DDR3L-2133 https://www.micron.com/-/media/client/global/documents/products/data-sheet/dram/ddr3/4gb_ddr3l.pdf?rev305217e2f9bd4ef48d7c6f353dfc064c
* CK(MIN) 0.938 ns
* CL 14 CK
* RCD(MIN) 14 CK
* RC(MIN) 50 CK
* RAS(MIN) 36 CK
* RP(MIN) 14 CK
* FAW 27 CK
* RRD 6 CK
* RFC 279CK
* XPR max(5CK, RFC10ns)
* MRD 4CK
* MOD max(12CK, 15ns)
* ZQinit max(512nCK, 640ns)
* DLLK 512CK
* command all p118
* initial waveform p137
*
* COMMAND | NOP | MRS_1 | MRS_2 | MRS_3 | MRS_4 | ZQCL
* ddr_cke | 1 1 | 1 1 | 1 1 | 1 1 | 1 1 | 1 1
* ddr_dqs_en | 0 | | | | |
* ddr_dq_en | 0 | | | | |
* ddr_cs_n | 0 | 0 | 0 | 0 | 0 | 0
* ddr_ras_n | 1 | 0 | 0 | 0 | 0 | 1
* ddr_cas_n | 1 | 0 | 0 | 0 | 0 | 1
* ddr_we_n | 1 | 0 | 0 | 0 | 0 | 0
* ddr_ba | vvv | 010 | 011 | 001 | 000 |
* ddr_addr | vvv | 28 | 00 | 44 | 124 | a[10]
* ddr_odt | 0 | | | | |
***************************************************************/
module micron_ddr_init #(parameter CLK_FREQ 1066.099, // MHzparameter _1MS_CYCLE 10.0**-3 / (1.0 / (CLK_FREQ * 10**6)),parameter _1US_CYCLE 10.0**-6 / (1.0 / (CLK_FREQ * 10**6)),parameter integer INITIAL_CYCLE 200 * _1US_CYCLE,parameter integer INITIAL_STABLE_CYCLE 500 * _1US_CYCLE,parameter integer FREE_CYCLE _1US_CYCLE
) (output reg [15:0] ddr_addr,output reg [2:0] ddr_ba,output reg ddr_cas_n,output reg [0:0] ddr_ck_n,output reg [0:0] ddr_ck_p,output reg [0:0] ddr_cke,output reg [0:0] ddr_cs_n,output reg [0:0] ddr_dm,inout [7:0] ddr_dq,inout [0:0] ddr_dqs_n,inout [0:0] ddr_dqs_p,output reg [0:0] ddr_odt,output reg ddr_ras_n,output reg ddr_reset_n,output reg ddr_we_n,input clk);localparam [27:0] NOP_CMD {11b11000111000, 16h0000, 1b0};
localparam [27:0] MRS1_CMD {11b11000000010, 16h0028, 1b0};
localparam [27:0] MRS2_CMD {11b11000000011, 16h0000, 1b0};
localparam [27:0] MRS3_CMD {11b11000000001, 16h0044, 1b0};
localparam [27:0] MRS4_CMD {11b11000000000, 16h0124, 1b0};
localparam [27:0] ZQCL_CMD {11b11000110000, 16h0400, 1b0};reg ddr_cke_p1, ddr_cke_p2;
reg ddr_dqs_i, ddr_dqs_o, ddr_dqs_en;
reg ddr_dq_i, ddr_dq_o, ddr_dq_en;OBUFDS OBUFDS_ck (.O(ddr_ck_p), // 1-bit output: Diff_p output (connect directly to top-level port).OB(ddr_ck_n), // 1-bit output: Diff_n output (connect directly to top-level port).I(clk) // 1-bit input: Buffer input);IOBUFDS #(.DQS_BIAS(FALSE) // (FALSE, TRUE))IOBUFDS_dqs_inst (.O(ddr_dqs_o), // 1-bit output: Buffer output.I(ddr_dqs_i), // 1-bit input: Buffer input.IO(ddr_dqs_p), // 1-bit inout: Diff_p inout (connect directly to top-level port).IOB(ddr_dqs_n), // 1-bit inout: Diff_n inout (connect directly to top-level port).T(ddr_dqs_en) // 1-bit input: 3-state enable input);IOBUF IOBUF_dq_inst (.O(ddr_dq_o), // 1-bit output: Buffer output.I(ddr_dq_i), // 1-bit input: Buffer input.IO(ddr_dq), // 1-bit inout: Buffer inout (connect directly to top-level port).T(ddr_dq_en) // 1-bit input: 3-state enable input);ODDRE1 #(.IS_C_INVERTED(1b1), // Optional inversion for C.IS_D1_INVERTED(1b0), // Unsupported, do not use.IS_D2_INVERTED(1b0), // Unsupported, do not use.SRVAL(1b0) // Initializes the ODDRE1 Flip-Flops to the specified value (1b0, 1b1))ODDRE1_cke_inst (.Q(ddr_cke), // 1-bit output: Data output to IOB.C(clk), // 1-bit input: High-speed clock input.D1(ddr_cke_p1), // 1-bit input: Parallel data input 1.D2(ddr_cke_p2), // 1-bit input: Parallel data input 2.SR(1b0) // 1-bit input: Active High Async Reset);//OBUFDS OBUFDS_dqs (
// .O(ddr_dqs_p), // 1-bit output: Diff_p output (connect directly to top-level port)
// .OB(ddr_dqs_n), // 1-bit output: Diff_n output (connect directly to top-level port)
// .I(ddr_dqs) // 1-bit input: Buffer input
// );reg [15:0] ddr_addr_r;reg [2:0] ddr_ba_r;reg ddr_cas_n_r;reg [0:0] ddr_cs_n_r;reg [0:0] ddr_dm_r; // no refreg [0:0] ddr_odt_r;reg ddr_ras_n_r;reg ddr_we_n_r;reg ddr_dq_en_r; reg ddr_dqs_en_r; initial begin{ddr_cke_p2, ddr_cke_p1, ddr_dqs_en, ddr_dq_en, ddr_cs_n, ddr_ras_n, ddr_cas_n, ddr_we_n, ddr_ba, ddr_addr, ddr_odt} NOP_CMD;{ddr_cke_p2, ddr_cke_p1, ddr_dqs_en_r, ddr_dq_en_r, ddr_cs_n_r, ddr_ras_n_r, ddr_cas_n_r, ddr_we_n_r, ddr_ba_r, ddr_addr_r, ddr_odt_r} NOP_CMD;endalways (negedge clk) beginddr_addr ddr_addr_r ;ddr_ba ddr_ba_r ;ddr_cas_n ddr_cas_n_r ;ddr_cs_n ddr_cs_n_r ;ddr_dm ddr_dm_r ;ddr_odt ddr_odt_r ;ddr_ras_n ddr_ras_n_r ;ddr_we_n ddr_we_n_r ;ddr_dq_en ddr_dq_en_r;ddr_dqs_en ddr_dqs_en_r;endreg [5:0] cs 0, ns;reg [31:0] initial_cnt 0;reg [31:0] initial_stable_cnt 0;reg [31:0] freerun_cnt 0;reg [3:0] initial_cmd_ptr 0;reg [27:0] initial_cmd_seq[0:5] {NOP_CMD, MRS1_CMD, MRS2_CMD, MRS3_CMD, MRS4_CMD, ZQCL_CMD};reg initial_finish 0;always (negedge clk) begincs ns;endalways (*) begincase (cs)0: beginif (initial_cnt INITIAL_CYCLE) begin // wait 200usns 1;end else beginns 0;endend1: begin // wait 500us if (initial_stable_cnt INITIAL_STABLE_CYCLE) begin // wait 500usns 2;end else beginns 1;endend2: beginns 3;end3: beginif (freerun_cnt FREE_CYCLE) beginif (initial_finish) beginns 4;end else beginns 2;endend else beginns 3;endend4: begin// finish initial, enter idle stateenddefault: beginns 0;endendcaseendalways (negedge clk) begincase (ns)0: begininitial_cnt initial_cnt 1;enddefault: begininitial_cnt 0;endendcaseendalways (negedge clk) begincase (ns)1: begininitial_stable_cnt initial_stable_cnt 1;enddefault: begininitial_stable_cnt 0;endendcaseendalways (negedge clk) begincase (ns)3: beginfreerun_cnt freerun_cnt 1;enddefault: beginfreerun_cnt 0;endendcaseendalways (negedge clk) begincase (ns)2: beginif (initial_cmd_ptr 6 - 1) begininitial_finish 1;end else begininitial_finish 0;endinitial_cmd_ptr initial_cmd_ptr 1;endendcaseendalways (negedge clk) begincase (ns)0: beginddr_reset_n 1b0;{ddr_cke_p2, ddr_cke_p1} 2b0;ddr_dqs_en_r 1b0;ddr_dq_en_r 1b0;end1: beginddr_reset_n 1b1;{ddr_cke_p2, ddr_cke_p1} 2b0;ddr_dqs_en_r 1b0;ddr_dq_en_r 1b0;end2: begin{ddr_cke_p2, ddr_cke_p1, ddr_dqs_en_r, ddr_dq_en_r, ddr_cs_n_r, ddr_ras_n_r, ddr_cas_n_r, ddr_we_n_r, ddr_ba_r, ddr_addr_r, ddr_odt_r} initial_cmd_seq[initial_cmd_ptr];end3: begin{ddr_cke_p2, ddr_cke_p1, ddr_dqs_en_r, ddr_dq_en_r, ddr_cs_n_r, ddr_ras_n_r, ddr_cas_n_r, ddr_we_n_r, ddr_ba_r, ddr_addr_r, ddr_odt_r} NOP_CMD;enddefault: beginddr_reset_n 1b1;endendcaseendendmodule上述代码已在Vivado 2017.4中进行了仿真测试可替换ddr示例工程中的example_top自行仿真。
