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现在正在用spartan6 xc6xls45配置DDR2内存,根据UG388,配置成DDR2 400,6个32bit port,其中p2用来写,p3用来读,其它端口不用。完后建立顶层文件调用IP核使用,已经实现了功能仿真,读出来的数据跟写入一样。
但是进行时序仿真时,碰见一个问题,DQS和UDQS信号不对,前两个数据是写不进去DDR2的,仿真错误信息如下:
sim_tb_top.\MEM_INST3.u_mem_c3 .data_task: at time 702937866.0 ps ERROR: DQS bit 0 latching edge required during the preceding clock periodsim_tb_top.\MEM_INST3.u_mem_c3 .data_task: at time 702937866.0 ps ERROR: DQS bit 1 latching edge required during the preceding clock period sim_tb_top.\MEM_INST3.u_mem_c3 .data_task: at time 702937866.0 ps ERROR: DQS_N bit 0 latching edge required during the preceding clock period sim_tb_top.\MEM_INST3.u_mem_c3 .data_task: at time 702937866.0 ps ERROR: DQS_N bit 1 latching edge required during the preceding clock period sim_tb_top.\MEM_INST3.u_mem_c3 .data_task: at time 702937866.0 ps INFO: WRITE @ DQS= bank = 0 row = 0000 col = 00000000 data = xxxx sim_tb_top.\MEM_INST3.u_mem_c3 .data_task: at time 702940305.0 ps ERROR: DQS bit 0 latching edge required during the preceding clock period. sim_tb_top.\MEM_INST3.u_mem_c3 .data_task: at time 702940305.0 ps ERROR: DQS bit 1 latching edge required during the preceding clock period. sim_tb_top.\MEM_INST3.u_mem_c3 .data_task: at time 702940305.0 ps ERROR: DQS_N bit 0 latching edge required during the preceding clock period. sim_tb_top.\MEM_INST3.u_mem_c3 .data_task: at time 702940305.0 ps ERROR: DQS_N bit 1 latching edge required during the preceding clock period.
断开对P2 P3端口的多有操作信号,还是出现这个情况,迷茫了,DQS和UDQS应该是硬核产生的信号,我还能怎样去控制呢?
这个是时序仿真的局部截图,很明显DQS信号少了一个周期 |