sc3200 Advanced Micro Devices, sc3200 Datasheet - Page 214

• Manufacturer Part Number: sc3200
• Description: Geode-tm Sc3200 Processor
• Manufacturer: Advanced Micro Devices

214
Index 54h-59h
Index 5Ah
Indicates PCI positive or negative decoding for various I/O ports on the ISA bus.
Note:
Index 5Bh
Note:
Table 6-29. F0: PCI Header/Bridge Configuration Registers for GPIO and LPC Support (Continued)
Bit
7
6
5
4
3
2
1
0
7
6
5
Positive decoding by the Core Logic module speeds up I/O cycle time. The I/O ports mentioned in the bit descriptions below, do
not exist in the Core Logic module. It is assumed that if positive decode is enabled for a port, the port exists on the ISA bus.
Positive decoding by the Core Logic module speeds up the I/O cycle time. The Keyboard, LPT3, LPT2, and LPT1 I/O ports do
not exist in the Core Logic module. It is assumed that if positive decoding is enabled for any of these ports, the port exists on
the ISA bus.
Description
Secondary Floppy Positive Decode. Selects PCI positive or subtractive decoding for accesses to I/O ports 372h-375h
and 377h.
0: Subtractive.
1: Positive.
Primary Floppy Positive Decode. Selects PCI positive or subtractive decoding for accesses to I/O ports 3F2h-3F5h and
3F7h.
0: Subtractive.
1: Positive.
COM4 Positive Decode. Selects PCI positive or subtractive decoding for accesses to I/O ports 2E8h-2EFh.
0: Subtractive.
1: Positive.
COM3 Positive Decode. Selects PCI positive or subtractive decoding for accesses to I/O ports 3E8h-3EFh.
0: Subtractive.
1: Positive.
COM2 Positive Decode. Selects PCI positive or subtractive decoding for accesses to I/O ports 2F8h-2FFh.
0: Subtractive.
1: Positive.
COM1 Positive Decode. Selects PCI positive or subtractive decoding for accesses to I/O ports 3F8h-3FFh.
0: Subtractive.
1: Positive.
Keyboard Controller Positive Decode. Selects PCI positive or subtractive decoding for accesses to I/O Ports 060h and
064h (as well as 062h and 066h, if enabled - F4 Index 5Bh[7] = 1).
0: Subtractive.
1: Positive.
Note:
Real-Time Clock Positive Decode. Selects PCI positive or subtractive decoding for accesses to I/O Ports 070h-073h.
0: Subtractive.
1: Positive.
Keyboard I/O Port 062h/066h Positive Decode. This alternate port to the keyboard controller is provided in support of
power management features.
0: Disable.
1: Enable.
Reserved. Must be set to 0.
BIOS ROM Positive Decode. Selects PCI positive or subtractive decoding for accesses to the configured ROM space.
0: Subtractive.
1: Positive.
ROM configuration is at F0 Index 52h[2:0].
If F0BAR1+I/O Offset 10h bits 10 = 0 and 16 = 1, then this bit must be written 0.
Revision 5.1
Decode Control Register 1 (R/W)
Decode Control Register 2 (R/W)
Reserved
Core Logic Module - Bridge, GPIO, and LPC Registers - Function 0
AMD Geode™ SC3200 Processor Data Book
Reset Value: 00h
Reset Value: 01h
Reset Value: 20h