You might like to read some tips and undocumented features on the CP88/CP73 I found, which are not mentioned in the manual:

- When you're lost in a submenu, the [MENU]-button returns you directly to the home-screen of the CP88/CP73.

- Notice the difference:
The assignment of the Assignable Foot Switch is a general setting, which affects all Live Sets (MENU-button).
The assignment of the two Foot Controllers is a setting that can be different on every Live Set Sound, where it's saved (SETTINGS-button).

- When assigning a function to a Foot Controller in a Live Set Sound there's a nice feature:
Select [SETTINGS] > Controllers > FC1 Assign (or FC2 Assign)
If you now operate a button or dial on the front panel of the instrument with your hand (for instance the VOLUME-dial of the Sub Section),
the corresponding Control Change Number automatically appears in the display!
You can confirm this setting using ENTER (push dial) and save it in a Live Set Sound using [STORE].

Funny detail:
If you move your foot on a foot controller that is assigned to a dial (for instance VOLUME-dial of the Sub Section: cc 30), you can see the led's turning
around the dial when changing the value with your foot (the Sub Section has to be switched on of course).
These leds also turn when you are assigning the foot controller, when you are in the menu mentioned above and move your foot on the controller.

This leds can also help you to calibrate the range of a non-Yamaha foot controller. I've used it to calibrate the Roland EV-5, which has a calibration dial
on the side, that needs to be just above the zero-position to work on my CP for a range from 0 to about 127.

- When you've assigned Foot Controller 2 to Sub Volume (like above), you can use this to add a Sub-sound to a Piano-sound while playing.
You can start playing with only the Piano sound (Sub Section is switched on, but Foot Controller is on minimum position) and slowly add the Sub-sound using the Foot Controller.
You can also fade out the Sub sound like this.

- When editing the name of a Live Set Sound or file:
[2] can also be used to add a space character to the end of the name
[5] moves also the cursor to the next position, so this works like an enter-button to enter a character

Notice that after you use the ENTER-button (push dial), you have to push [STORE] to actually save the edited name of the Live Set Sound on the desired Live Set Sound position!
A Live Set Sound name can be max 15 characters.

- Do you wonder why the CP80 sounds are part of the Piano Section and not the Electric Piano section?
It's because the original sampled instruments in the Piano section all have piano strings, unlike electric piano's.

Have fun and do experiment to find more special features!