These instructions assume the following: (a) Keystep rear switches - USB, (b) Keystep connected to Mac via USB cable, (c) Logic Pro X (LPX) (Version 10.4.8.).
1. On Mac, open Arturia Midi Control Center (free download from Arturia’s website) , use standard settings and under Transport Settings at the bottom, ensure Play/Pause is set to "Reset" and that Transport Mode is set to "MIDI CC." (MIDI Continuous Controller). Each knob, button, fader, etc. on the Keystep (or any controller for that matter) can potentially be programmed to control a DAW function. This enhances the workflow by reducing the functions that have to be accessed via two or more devices (e.g., controller, DAW, iPad, etc.).
2. Open Logic Pro X (LPX) ⟶ LPX (top left menu) ⟶ Key Commands ⟶ Edit (shortcut: option + k) ⟶ highlight "Pressed" in top menu ⟶ highlight "Record" under Global Commands ⟶ select "Learn New Assignment" under Assignments (lower right of window) ⟶ push Keystep’s Record (append) button. (You should now see information in the Assignments window (e.g., Control Change Ch 1, 50, 127: Learned). If not, delete the assignment in the Assignments window and start over.
3. Repeat the steps in 2. above for Play and Stop in LPX and on the Keystep.
4. The transport controls for Record, Play, and Stop on the Keystep should now control the same in LPX via the MIDI CCs.
5. In LPX, select File (top menu) ⟶ Project Settings ⟶ Synchronization ... ⟶ Midi ⟶ Under "Destination" select "Arturia Keystep 32" ⟶ ensure "Clock” is NOT selected.
6. There are other ways to do this. For example, Midi Machine Control (MMC) can also be used, but I find the controls do not behave exactly like within LPX without a controller (e.g., the way the stop button stops first, then resets. And the way the play button resets when pressed).
7. To try this method: In step 1. above, select MMC or BOTH instead of MIDI CC. Then, In LPX, select File (top menu) ⟶ Project Settings ⟶ Synchronization ... ⟶ Midi ⟶ Select “Listen for MIDI Machine Control (MMC)" ⟶ Under "Destination" select "Arturia Keystep 32" ⟶ ensure "Clock” is NOT selected.
8. Be advised that the above setup will not allow the use of Keystep's built-in sequencer and Arp because when the rear switches are set to USB the Keystep is in "Slave" mode in terms of the clock (please correct me if I am wrong on this because I have not tested this function).
9. Please let me know if this works for you. Good luck!
Zab