一、问题描述

最近在用Xilinx FPGA做一个东西，在此过程中，发现如果写的代码消耗的bram资源超过一定数目，vivado implementation就会失败，且Messages没有错误信息，如下图：

lmplementation Run Properties 中显示：

Finished Running Vector-less Activity Propagation
INFO: [Pwropt 34-322] Received HACOOException
WARNING: [Pwropt 34-321] HACOOException: Too many TFIs and TFOs in design, exiting pwropt. You can change this limit with the param pwropt.maxFaninFanoutToNetRatio
INFO: [Pwropt 34-232] Skipping BRAM gating because all BRAMs are in high frequency (i.e. period < 3.12 ns) clock domains.
INFO: [Pwropt 34-162] WRITE_MODE attribute of 0 BRAM(s) out of a total of 80 has been updated to save power. Run report_power_opt to get a complete listing of the BRAMs updated.
Abnormal program termination (EXCEPTION_ACCESS_VIOLATION)
Please check 'E:/CODE/FPGA/wujian100/test1/wujian100_open-master/fpga/vivado/wujian100_test1/wujian100_test1.runs/impl_1/hs_err_pid14172.log' for details

hs_err_pid14172.log文件里显示：

#
# An unexpected error has occurred (EXCEPTION_ACCESS_VIOLATION)
#
Stack:
no stack trace available, please use hs_err_<pid>.dmp instead.

二、解决方法
在Tcl Console中输入如下命令，再重新lMPLEMENTATION就不会出错了。

set_param pwropt.maxFaninFanoutToNetRatio 2000

原因是：

参考资料

https://support.xilinx.com/s/question/0D52E00006hpmJ7SAI/pwropt-34321-hacooexception-too-many-faninfanouts-in-design-exiting-pwropt-you-can-change-this-limit-with-the-param-pwroptmaxfaninfanouttonetratio?language=en_US