W83977F Datasheet, PDF (126/181 Pages) Winbond – PLUG & PLAY 1.0A COMPLIANT

W83977F/ W83977AF
8.2.3 Power LED
PRELIMINARY
The Power LED function provides 1 Hertz rate toggle pulse output with 50 percent duty cycle. Table
8.2.2 shows how to enable Power LED.
Table 8.2.2
WDT_CTRL1 BIT[1] WDT_CTRL0 BIT[3] WDT_CTRL1 BIT[0] POWER LED STATE
1
X
X
1 Hertz Toggle pulse
0
0
X
Continuous high or low *
0
1
0
Continuous high or low *
0
1
1
1 Hertz Toggle pulse
* Note: Continuous high or low depends on the polarity bit of GP13 or GP17 configure registers.
8.2.4 General Purpose Address Decoder
General Purpose Address Decoder provides two address decode as AEN equal to logic 0. The
address base is stored at CR62, CR63 of logical device 7. The decode output is normally active low.
Users can alter its polarity through the polarity bit of the GP14's configuration register.
8.2.5 General Purpose Write Strobe
General Purpose Write Strobe is an address decoder that performs like General Purpose Address
Decoder, but it has to be qualified by IOW and AEN. Its output is normally active low. Users can
alter its polarity through the polarity bit of the GP15's configuration register.
9. PLUG AND PLAY CONFIGURATION
The W83977F/ AF provides many configuration registers for setting up different types of
configurations. There are two approaches to entering the configuration state and accessing these
configuration registers, Comply PnP and Compatible PnP. The Comply PnP protocol is based on the
Plug and Play ISA Specification. The Compatible PnP protocol is similar to previous Winbond I/O's
protocol. The Power-On-Setting upon the Pin 51 (DTRB ) decides the method of entering the
configuration mode. In W83977F/ AF, there are nine Logical Devices (from Logical Device 0 to
Logical Device 8) which correspond to nine individual functions: FDC, PRT, UART1, UART2, RTC,
KBC, IR, GPIO1, GPIO2 in listed order. Each Logical Device has its own configuration registers
(above CR30). Host can access those registers only after entering configuration mode.
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Publication Release Date: March 1998
Revision 0.58