Standby Mode; Suspend Modes; Suspend-To-Ram Mode; Save-To-Disk Mode - Fujitsu Stylistic 3400 Technical Reference Manual

System Activity
Stop Grant
(STPCLK#)
Internal CPU Clock
Signals
External Clock
Signals
Hard Disk Drive
Display
* Power saving timeouts can be configured independently for these devices allowing them to enter a low-power state
while the system is in Idle mode.
Note that this table does not depict a precise timing diagram. The illustrations given in this table are intended to
show the relative characteristics of these signals.

Standby Mode

Standby mode is entered when the Standby Mode Timeout (configured in the BIOS) occurs. In Standby
mode, the CPU, supporting chip set, and RAM remain powered, however, the CPU's internal clock
signals are stopped (effectively stopping the CPU) as indicated in Table 7-3. Any user activity that
generates an interrupt will cause a transition out of the Standby state to the Fully On state.
The hard disk drive is forced into standby mode (spun down) when the standby mode timeout occurs.
Note, however, that the hard disk drive can be configured to spin down earlier by setting the HDD
Spin-down Timeout BIOS option. The display system (including backlight) is also turned off when the
standby timeout occurs. The display can also be configured to turn off earlier by setting the Video
Timeout BIOS option.

Suspend Modes

The system can be configured to use one of two different suspend modes: Suspend-to-RAM or
Save-to-Disk. System power activity in each of these modes is described below.

Suspend-to-RAM Mode

In Suspend-to-RAM mode, power is maintained to RAM, video memory, and circuitry for the Suspend/
Resume button while all other system circuitry and power managed devices are powered off. The PC
Card slot will also remain powered if the Resume On Modem Ring option is enable in the BIOS. Pressing
the Suspend/Resume button, or a resume request generated by a modem ring will cause a transition to
the Fully On state. Suspend-to-RAM mode is best suited for applications where system operation is
suspended frequently and a quick resume is desired.

Save-to-Disk Mode

In Save-to-Disk mode, data in RAM and video memory are written to the hard disk drive and, with the
exception of resume logic circuits connected to the Suspend/Resume button switch, the system is

Table 7-3. System Activity in Idle and Standby Modes

Idle Mode
On*
On*
Power Management States and BIOS Configuration Options
Standby Mode
Standby (spin down)
Off
7
7
7
7
72