This example will show how to modify audio input/output port type in DPF so they can work as CV.
Take a look at
Worth noting that CV is not supported outside of JACK and LV2 formats.
While it can be built and used in other formats, these ports will appear as regular audio to the host.
The plugin does sample & hold (S&H) processing.
3 I/O ports are specified.
The plugin also has a Hold Time parameter. It mixes CV value and parameter value.