W83C553F Datasheet, PDF (65/159 Pages) Winbond – SYSTEM I/O CONTROLLER WITH PCI ARBITER

W83C553F
Electrical Specifications
BIOS Timer Base Address Register (default = 0078h)
Type:
Read/Write
Function:
The base address for the BIOS Timer Register located in PCI I/O space. The BIOS Timer resides in the
W83C553F and is the only internal resource mapped to PCI I/O space.
Bit Description:
Bits [15:2]:
Bit 1:
Bit 0:
BTMRBA. BIOS Timer Base Address. This register specifies the Base Address 15:2 for the
BIOS Timer register located in the I/O space. The lower two bits of the base address are 00
(Dword aligned). The value of this register points to 78h (0000_0000_0111_10xx) after a reset.
Reserved.
BTMRE. Timer Enable. When this bit is set to "1", the BIOS timer function is enabled and the
base address of the timer registers is programmed in Bits [15:2].
WINBOND SYSTEMS LABORATORY
62