Any Xilinx users from back in the day who can give me some advice?
I’m playing with old Xilinx stuff and can’t quite get a design going in XACT. I’ve got a simple example in ABEL from Xilinx. It’s a 3-bit, 7-state counter which is decoded into seven one-hot outputs. (Source attached; it’s basically straight from Xilinx)
During synthesis, the XNFPREP logic optimizer ends up trimming all the logic in the design under the impression that the clock signal is sourceless. The apparent solution for this was to use the -savesig option: "don't trim sourceless or loadless signals.” Then the design maps and P&Rs with apparent success, but then the same issue is manifest in the routed FPGA. The logic is in there but there are no connections to the IO blocks. (see attached picture)

I was under the impression that if I didn’t make any pin assignments, the fitter would choose for me like in new tools. Is that not correct? Do I need some kind of top-level entity other than the ABEL file? Pin constraints file? I’m lost with these old tools lol… Also, any signal named “A” is always totally removed somewhere in the process. I changed it to “OUTA” and it didn’t get deleted. I guess it’s some kind of reserved identifier somewhere. But that’s not the main issue.
Anyone know what I’m doing wrong here?