I/O Addressing - NEC PowerMate V486 Series Service Manual

1-8 Technical Information
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 V4100) 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.

I/O Addressing

The processor communicates with I/O devices by I/O mapping. The hexadecimal (hex) ad-
dresses of I/O devices are listed in Table Section 1-5.
Address (Hex)
000-01F
020-03F
040-05F
060-063
060-06F
070-07F
080
081-09F
0A0-0AF
092
094
095
097
Table Section 1-5 I/O Address Map
I/O Device Name
DMA controller 1 (channel 0-3)
Interrupt controller
Timer
PPI (Programmable Peripheral Interface) keyboard, equipment switches,
timer
Keyboard controller
Real-time clock, CMOS memory, NMI mask
Manufacturer's diagnostic checkpoint
DMA page register
NMI (non-maskable interrupt) mask
PS/2 alternate Fast A20 Gate, Hot Reset
Extended system port (NEC-specific hardware setup)
Extended system port (NEC-specific hardware setup)
Extended system port (NEC-specific hardware setup)