AR# 4074: M1.4 PAR - DRC incorrectly posts warning about DPRAM D1 pin when it is unused.
M1.4 PAR - DRC incorrectly posts warning about DPRAM D1 pin when it is unused.
WARNING:x4edr:21 - Blockcheck: CLB "U8_uart_ctl_i_txfifo_out<28>" is configured to use the G LUT as RAM, but the D1 and WE lines use the same pin, which will likely cause a D->WE setup violation.
The SR mux is driving WE. The same signal drives the H-LUT thru the H1 mux. Because the H1 mux also drives D1, drc warns about the setup violation. This is an incorrect warning because the DPRAM configuration does not use D1.
This problem has been fixed for the M1.5 release. Meanwhile the incorrect warning message can be safely ignored in M1.4 by running bitgen with the -d option to disable drc.