FPGA : difference between Constant output node and the combination "Set output enable -- Set output data" ?

[CyGa]

In order to produce the best code possible, I'd like to know what is the difference (SW and HW) between Constant output node and the combination "Set output enable -- Set output data"...
Thanks !

[jakidd]

I would like to know the same thing too.

[ElRambo]

Hi Zyl7,

If you are only doing digital output, generally the FPGA I/O Node is all you need.  It writes the data and enables the resource for output.  However, the opposite is not true for digital input.   The FPGA I/O Node reads the data but does not change the input/output direction.  Typically the default state for a DIO port is input.  Once it is used for output, the Set Output Enable method must be used to change the resource back to an input. 

There are other cases when you may want to use the "Set output enable -- Set output data" methods instead of an I/O node.  For instance, you may have different data values but only want to enable output at a particular time.

A good description is in the Performing FPGA I/O (FPGA Module) topic in the LabVIEW Help. 

Regards,