Can I trust it completely?When pins are auto assigned.

[75 sinfocia]

After my EPM7128LC84-6 was auto assigned pins ,I found that the 84th pin(INPUT/OE1) was assigned as a 'in' pin. The 1st pin(INPUT/GLCRn) and the second pin(INPUT/OE2) were 'GND'.What should i do,trust them or amend them?

 

[mutoucanada]

After my EPM7128LC84-6 was auto assigned pins ,I found that the 84th pin(INPUT/OE1) was assigned as a 'in' pin. The 1st pin(INPUT/GLCRn) and the second pin(INPUT/OE2) were 'GND'.What should i do,trust them or amend them?

I think you should reassign the pins.

 

[wjhzhx]

You should assign the pin according your CPLD's pin connection on the PCB, the software assigns these "INPUT/GLCRn) and the second pin(INPUT/OE2) were 'GND' " is that these pin is not used in your design, it is best to tie them to GND.

 

[linuxluo]

Hi,
I think you can believe the auto place pin. And the result of auto is best normally than you place pin manually.

 

[cbh1024]

FPGA Pin Assignment

One possible pin assignment method is to

1. First allow the FPGA software to route your initial design and give you a set of pin allocations.

2. Design your PCB based on this pin assignment and FIX this pin assignment so that any future iterations of resynthesis and P&R will not deviate much from this pin assignment.

Generally the pin assignment provided by the FPGA P&R tool is optimized for its P&R.

And of course reserve plenty of IOs to external connectors on your board in case you want to use extra signals.