General Description: The following error can occur in map
ERROR:x4kma:339 - The CY4 symbol "signal_name" (output signal=signal_name) has no signal connected to A0. This pin must be connected based on carry moded ADD-G-F1
A possible cause of this error is the incorrect connection of a non-GSR signal to GSR pins on symbols (DFF's in this case) in the design. NGDBUILD assumes that only a GSR signal will be connected to these pins, so it removes the entire signal including the connections to the CY4 symbols involved in the error, leading to the error.
解决方案
1
This error will also occur if there are missing connections in the design (i.e. undriven signals or buses). The designer will need to find the is a impeding signals and modify the design.
2
Ensure that there are not any non-GSR signals connected to the GSR net. If the design is a schematic design, this should be straight forward. If it is a HDL design, verify that the code is correct. Also, verify that the XNF does not contain any incorrect GSR connections. An example from an XNF is:
PIN, GSR, I, signal_name,
If there are no incorrect connections to the GSR in the design, and yet the XNF still contains them, it is possible to simply delete these references in the XNF. This workaround will allow the design to be properly implemented, and still contain the exact functionality desired.