
82C814
Page 2
January 08, 1998
912-3000-047
Revision: 1.0
OPTi
3.0
Signal Definitions
The 82C814 chip provides a primary interface which is PCI-
based. It also provides an independent attachment interface,
which can be switched on and off dynamically. 
3.1
Terminology/Nomenclature 
Conventions
The “#” symbol at the end of a signal name indicates that the
active, or asserted state occurs when the signal is at a low
voltage level. When “#” is not present after the signal name,
the signal is asserted when at the high voltage level.
The terms “assertion” and “negation” are used extensively.
This is done to avoid confusion when working with a mixture
of “active low” and “active high” signals. The term “assert”, or
“assertion” indicates that a signal is active, independent of
whether that level is represented by a high or low voltage.
The term “negate”, or “negation” indicates that a signal is
inactive.
The 82C814 has some pins that have multiple functions
(denoted by “+” in the pin name). These functions are either:
 cycle-multiplexed (always enabled and available when a 
particular cycle is in progress),
 a strap option (configured at reset),
 or selected via register programming. 
The tables in this section use several common abbreviations.
Table 3-1 lists the mnemonics and their meanings. 
Table 3-1
Signal Definitions Legend
Mnemonic
Description
CMOS
CMOS-level compatible
Dcdr
Decoder
Ext
External
G
Ground
I
Input
I/O
Input/Output
Int
Internal
Mux
Multiplexer
O
Output
OD
Open drain (open-collector) CMOS-
level compatible
P
Power
PD
Pull-down resistor
PU
Pull-up resistor
S
Schmitt-trigger TTL-level compatible
TTL
TTL-level compatible