W83977F Datasheet, PDF (127/181 Pages) Winbond – PLUG & PLAY 1.0A COMPLIANT

9.1 Comply PnP
W83977F/ W83977AF
PRELIMINARY
The protocol of Comply PnP is 100% compatible with the Plug and Play ISA Specification.
W83977F/ AF provides built-in Plug and Play state machine to control the configuration flow. The
state machine supports four states: Wait for Key state, Sleep state, Isolation state, and Configure
State. According to Plug and Play ISA Specification, users can transit the four states by accessing
the configuration registers, CR00 - CR07.
9.1.1 Wait for Key State
All cards enter this state after power-up reset or in response to the Reset and Wait for Key
commands. No command is active in this state until the initiation key is detected on the ISA bus. The
initiation key is a sequence of 32 hexadecimal number which will be shifted into LFSR (linear
feedback shift register) built in W83977F/ AF. The Wait for Key state is the default state for Plug and
Play cards during normal system operation. After configuration and activation, software should return
all cards to this state.
9.1.2 Sleep State
In this state, Plug and Play wait for a Wake[CSN] command. This command will selectively enable
one or more cards to enter either the Isolation or Configure states based on the write data and the
value of the CSN on each card. If the write data for the Wake[CSN] command is zero then all cards
that have not been assigned a CSN will enter the Isolation state. If the write data for the Wake[CSN]
command is not zero then the one card whose assigned CSN matches the parameter of the
Wake[CSN] command will enter the Configure state.
9.1.3 Isolation State
In this state, Plug and Play cards respond to reads of the Serial Isolation registers according to
Isolation protocol. An unique CSN is assigned after the card is isolated
9.1.4 Configure State
A card in the Configure state responds to all configuration commands including reading the card's
resource configure information and programming the card's resource selections. Only one card may
be in this state at a time.
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Publication Release Date: March 1998
Revision 0.58