w83627sf Winbond Electronics Corp America, w83627sf Datasheet - Page 96

• Manufacturer Part Number: w83627sf
• Description: Winbond I/o
• Manufacturer: Winbond Electronics Corp America

9. PLUG AND PLAY CONFIGURATION
The W83627SF uses Compatible PNP protocol to access configuration registers for setting up different
types of configurations. In W83627SF, there are twelve Logical Devices (from Logical Device 0 to Logical
Device C with the exception of logical device 4 for backward compatibility) which correspond to eleven
individual functions: FDC (logical device 0), PRT (logical device 1), UART A (logical device 2), UART B
(logical device 3), KBC (logical device 5), CIR (Consumer IR, logical device 6), GP1 (logical device 7),
GP2 (logical device 8), GP3 and GP4 (logical device 9), ACPI ((logical device A), Smart Card interface
(logical device B), and GP5, GP6, and GP7 (logical device C).
configuration registers (above CR30). Host can access those registers by writing an appropriate logical
device number into logical device select register at CR07.
9.1 Compatible PnP
9.1.1 Extended Function Registers
In Compatible PnP, there are two ways to enter Extended Function and read or write the configuration
registers. HEFRAS (CR26 bit 6) can be used to select one out of these two methods of entering the
Extended Function mode as follows:
After Power-on reset, the value on RTSA# (pin 43) is latched by HEFRAS of CR26. In Compatible PnP,
a specific value (87h) must be written twice to the Extended Functions Enable Register (I/O port address
2Eh or 4Eh). Secondly, an index value (02h, 07h-FFh) must be written to the Extended Functions Index
Register (I/O port address 2Eh or 4Eh same as Extended Functions Enable Register) to identify which
HEFRAS
0
1
write 87h to the location 2Eh twice
write 87h to the location 4Eh twice
address and value
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Each Logical Device has its own
Publication Release Date: Nov. 2000
PRELIMINARY
W83627SF
Revision 0.60