Power Management - NEC POWERMATE 4100M Service Manual

Flash ROM supports the reprogramming of the system and built-in video BIOS. Software
controls this feature via port 94h. Flash ROM programming writes to location 0F0000h-
0FFFFFh. This range allows access to 64 KB of the 128 KB ROM. To write to the rest of
the ROM, bit 3 of port 94h must be set. Again, writing to 0F0000h-0FFFFFh allows the
rest of the ROM to be programmed. (Setting bit 3 on port 94h maps the 0F0000h to
0E0000h range.)

Power Management

Each computer system incorporates power management features that lowers power con-
sumption when there is no activity detected from the keyboard, mouse, diskette drive, CD-
ROM reader, or hard disk drive after a pre-defined period of time. As soon as activity is
detected the system resumes where it left off.
When Power Management is enabled the computer automatically activates power-saving
features and enters a sleep mode whenever inactivity is sensed. The computer's power-
saving functions are as follows.
n
Reduces the CPU clock speed
The CPU clock speed is changed from 33 MHz to 8 MHz (16 MHz in the
PowerMate 4100M) to put the computer in sleep mode. The cache and video
clocks are changed at the same time.
n
Blanks out the monitor
Puts the video controller into sleep mode. The vertical sync clock and blank sig-
nals to the monitor are disabled.
n
Forces the IDE devices into stand-by mode
A suspend command is sent to the IDE devices which put the devices into a
stand-by mode.
Technical Information 1-7