HP Vectra VL 5/xxx 5 manual Serial Eeprom, Described on, Bytes of Cmos memory

2 System Board

Chip-Set

	described on page 37.
RTC	The real-time clock (RTC) is 146818A-compatible. With an accuracy of
	20 ppm (parts per million). 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).

General Purpose I/O There are several general purpose I/O pins. Some of these are used on the HP Vectra to sense the current settings of system board switches (page 31 and page 39).

Description	GPIO number
Reserved (HP security from Little Ben IRQ)	GPIO10
Ratio of processor frequency to processor local bus frequency (as per SW-4)	GPIO11
Auto soft lock	GPIO12
Backplane identification BPID0 (always =0); (see BPID1, below)	GPIO13
Host bus frequency selection, as indicated by SW-1	GPIO14
Host bus frequency selection, as indicated by SW-2	GPIO15
Serial EEPROM clear (as per SW-6)	GPIO16
Ratio of processor frequency to processor local bus frequency (as per SW-3)	GPIO17
Backplane identification BPID1 (desktop=1, minitower=0)	GPIO20
Serial EEPROM data out	GPIO21
Serial EEPROM data in	GPIO22
Serial EEPROM clock	GPIO23
Serial EEPROM chip select	GPIO24
Reserved (for fax or general purpose light)	GPIO25

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