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HUD程序中使用的UCF约束

作者:互联网

1、注释使用#或//,而非verilog中的/*   */

2、周期时钟约束

NET "sysclkin_50M" TNM_NET = "CLK_IN1";
TIMESPEC "TS_CLK_IN1" = PERIOD "CLK_IN1" 50.0 ns HIGH 50%;

NET "sysclkin_50M" CLOCK_DEDICATED_ROUTE = FALSE;

NET  "sysclkin_50M"                                 IOSTANDARD = LVCMOS33 ;
NET  "sysclkin_50M"                                 LOC = "AB13" ;//"Y13" ;

第一条约束定义时钟sysclkin_50M驱动的所有同步器件为一个分组,即CLK_IN1;

第二条约束定义CLK_IN1时钟组其周期为50ns,即20MHZ,占空比为50%,波形产生第一个点评为高电平。

第三条特殊时钟约束:CLOCK_DEDICATED_ROUTE,当时钟从普通IO输入非时钟网络引脚输入时,FPGA会产生报警,若想要忽略并继续工作定义该条约束即可

第四条约束定义管脚电器类型为LVCMOS33

第五条约束定义管脚位置,即将sysclkin_50M约束到管脚AB13上

3、约束辅助电压VCCAUX电压值

CONFIG VCCAUX=3.3;

4、ddr约束

NET "mcb3_dram_dq[*]"                                 IN_TERM = NONE;
NET "mcb3_dram_dqs"                                   IN_TERM = NONE;
NET "mcb3_dram_dqs_n"                                 IN_TERM = NONE;
NET "mcb3_dram_udqs"                                  IN_TERM = NONE;
NET "mcb3_dram_udqs_n"                                IN_TERM = NONE;

以上几条是用来约束内部阻抗的,此处内部阻抗为无

NET  "mcb3_dram_dq[*]"                               IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_a[*]"                                IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_ba[*]"                               IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_dqs"                                 IOSTANDARD = DIFF_SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_udqs"                                IOSTANDARD = DIFF_SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_dqs_n"                               IOSTANDARD = DIFF_SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_udqs_n"                              IOSTANDARD = DIFF_SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_ck"                                  IOSTANDARD = DIFF_SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_ck_n"                                IOSTANDARD = DIFF_SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_cke"                                 IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_ras_n"                               IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_cas_n"                               IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_we_n"                                IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_odt"                                 IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_dm"                                  IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_dram_udm"                                 IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_rzq"                                      IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;
NET  "mcb3_zio"                                      IOSTANDARD = SSTL18_II  |OUT_TERM = UNTUNED_50;

以上几条用来对信号进行约束,IOSTANDARD 约束电气标准,

OUT_TERM约束为非ip core建议匹配,约束外部阻抗,强制要求匹配阻抗为50Ω

 

标签:HUD,IOSTANDARD,TERM,50,约束,UCF,dram,NET,mcb3
来源: https://www.cnblogs.com/gaoyong-512/p/10613806.html