FUJITSU MHV2060BH - Manual (Page 246)

Operations
6-12 C141-E224
(3) Slumber mode
In this mode, the (deep) Power Save mode is set for the interface circuit.
The device switches to Slumber mode when the following occurs:
• The device receives the PMREQ_P signal from the host and responds with
the PMACK signal
• The device sends the PMREQ_S signal and the host responds with PMACK
signal.
The device cannot switch to Slumber mode if the following condition is satisfied:
• The device responds with the PMNAK signal because it is not waiting for
commands.
The device returns to Active mode from Slumber mode when the following
condition is satisfied:
• The device receives the COMRESET or ComWake signal from the host.