Internal Error: Sub-system: VPR20KMAIN, File: /quartus/fitter/vpr20k/altera_arch_common/altera_arch_re_network_routing_constraints.cpp, Line: 654 - Internal Error: Sub-system: VPR20KMAIN, File: /quartus/fitter/vpr20k/altera_arch_common/altera_arch_re_network_routing_constraints.cpp, Line: 654 Description Due to a problem in the Intel® Quartus® Prime Pro Edition software version 19.1, you may see this internal error during the fitter stage of compilation. Resolution To work around this problem, remove or disable all VIRTUAL_PIN assignments which refer to signals *_ptp*. This problem has been fixed beginning with version 19.3 of the Intel® Quartus® Prime Pro Edition software. Custom Fields values: ['novalue'] Troubleshooting 1807853252 False ['novalue'] ['FPGA Dev Tools Quartus® Prime Software Pro'] 19.3 19.1 ['Programmable Logic Devices'] ['novalue'] ['novalue'] ['novalue']