Hi,
I have several nodes in my design (registered nodes) which do not have a "driving" purpose. But for later use of SignalTap (Altera tool to make internal FPGA nodes visible) I do want the synthesizer not to optimize these nodes away. On the other hand I do not want to route these nodes to output pins because of a limited amount of available pins.
Is there some possibility to avoid that these registerd not used nodes are optimized away ?
Thank you for your suggestion.
Rgds André
There are synthesis pragmas which you can use to keep these registers (syn_keep for synplicity etc.). If you have too much difficulty convincing either the synthesizer or the mapper to keep these unused registers, you can "or" the outputs of multiple registers and route it to a single output pin which should vastly reduce your pin availability concerns.
Hi,
One thing that might work is to drive them to outputs and then define those outputs as virtual pins with the assignment editor. They will not be synthesised away.
hope this helps.
Christos Zamantzas
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