21
2 System Board
Devices on the ISA Bus
FDC
The integrated
flexible drive controller
(FDC) supports any combination of
two from the following: tape drives, 3.5-inch flexible disk drives, 5.25-inch
flexible disk drives. It is software and register compatible with the 82077AA,
and 100% IBM compatible. It has an A and B drive-swapping capability and a
non-burst DMA option.
Keyboard and Mouse
Controller
The computer has an 8042-based keyboard and mouse controller (the
connector pin layouts are shown on page 33). The computer is supplied with
a Logitech 2-button mouse, and a C3758A keyboard with the following
features:
❒
Space bar power on, to start the computer from the
Off
state (if
power on
from keyboard
is enabled in the
Setup
program).
❒
Windows key (next to the
keys), which has the same effect as
clicking the “Start” button on the Windows 95 task bar.
❒
Pull-down key (next to the right
key), which has the same effect as
clicking the right mouse button.
RTC
The real-time clock (RTC) is 146818A-compatible. The configuration RAM
is implemented as 256 bytes of CMOS memory.
Serial EEPROM
This is the non-volatile memory which holds the default values for the CMOS
memory (in the event of battery failure, or the user pressing
in
Setup
).
When installing a new system board, the Serial EEPROM will have a blank
serial number field. This will be detected automatically by the BIOS, which
will then prompt the user to enter the serial number which is printed on the
identification label on the back of the computer.
General Purpose I/O
The NS87308 and NS87307 provide a number of general purpose I/O pins.
Some of these are used on the
HP Vectra VE 5/xxx series 3
to sense the
current settings of system board switches and jumpers.
Description
GPIO number
Host bus frequency selection (S2), as indicated by jumper J7
GPIO10
Host bus frequency selection (S1), as indicated by jumper J7
GPIO11
Level-2 cache memory size determination (KPRES2)
GPIO12
Level-2 cache memory size determination (KPRES1)
GPIO13
Ratio of Processor frequency to Processor Local Bus frequency (as per SW2)
GPIO14
Ratio of Processor frequency to Processor Local Bus frequency (as per SW2)
GPIO15
Содержание Vectra VE5 3
Страница 1: ...Technical Reference Manual Hardware and BIOS HP Vectra VE series 3 PC ...
Страница 8: ...Contents viii ...
Страница 16: ...8 1 System Overview Documentation ...