The ap_none specifies that no I/O protocol
be added to the port. When this is specified the argument is implemented as a data port with
no other associated signals. The ap_none mode is the default
for scalar inputs.
ap_none
The ap_none port-level I/O protocol is
the simplest interface type and has no other signals associated with it. Neither the input
nor output data signals have associated control ports that indicate when data is read or
written. The only ports in the RTL design are those specified in the source code.
An ap_none interface does not require
additional hardware overhead. However, the ap_none interface
does requires the following:
- Producer blocks to do one of the following:
- Provide data to the input port at the correct time
- Hold data for the length of a transaction until the design completes
- Consumer blocks to read output ports at the correct time
Note: The
ap_none interface cannot be used with array arguments.