TP is correct, no such number in FCOM. An ECAM warning is described under Abnormals in book 3:
ENG 1(2) LOW N1 (on ground)
No N1 rotation during start- THR LEVER (affected) .................................. IDLE
- ENG MASTER (affected) .................................OFF
Usually more information on trigger values is found in book 1 under Warning & Cautions for the given system. In this case however, the only description is "No N1 rotation during start".
Sincerely,
FD (the un-real)