Intel® 460GX Chipset Software Developer’s Manual
11-15
LPC/FWH Interface Configuration
11.1.27.3
Test Mode Register
Address:
FC-FFh
Default Value:
00000000h
Attributes:
Read/Write
11.2
PCI to LPC I/O Space Registers
11.2.1
DMA Registers
The IFB contains DMA circuitry that incorporates the functionality of two 82C37 DMA controllers
(DMA1 and DMA2). The DMA registers control the operation of the DMA controllers and are all
accessible from the Host CPU via the PCI Bus interface.
11.2.1.1
Dcom–Dma Command Register (I/O)
I/O Address:
Channels 0-3–08h; Channels 4-7–0D0h
Default Value:
00h (CPURST or Master Clear)
Attribute:
Write Only
This 8-bit register controls the configuration of the DMA. Note that disabling channels 4-7 also
disables channels 0-3, since channels 0-3 are cascaded onto Channel 4.
7:4
FWH_C8_IDSEL: This dictates the IDSEL of 512 KB of the FWH memory range starting at 4 GB -
3.5 MB (FFC80000H) to 4 GB - 3 MB (FFCFFFFFH) as well as register space starting at (4 GB-
4MB) - 3.5MB (FF880000h) to (4 GB-4MB) - 3MB (FF8FFFFFh). The enable for this range is
controlled through bit 1 of the FWH Decode Enable Register at E3H.
3:0
FWH_C0_IDSEL: This dictates the IDSEL of 512 KB of the FWH memory range starting at 4 GB -
4 MB (FFC00000H) to 4 GB - 3.5 MB (FFC7FFFFH) as well as register space starting at (4 GB-
4MB) – 4MB (FF800000h) to (4 GB-4MB) - 3.5MB (FF87FFFFh). The enable for this range is
controlled through bit 0 of the FWH Decode Enable Register at E3H.
Bit
Description
Bit
Description
31:1
Reserved.
0
Alternate Access Mode Enable: When set, the part enters alternate access mode. This allows
reads to certain write-only registers and writes to certain read-only registers. Read to Port 70h will
return the NMI mask value. See Section 10.3 of the RS-IFB (I/O & Firmware Bridge) External
Design Specification, Rev 2.0, for more detail.
Bit
Description
7
Reserved. Must be 0.
6
Reserved. Must be 0.
5
Reserved. Must be 0.
4
DMA Group Arbitration Priority. 1=Rotating priority; 0=Fixed priority
3
Reserved. Must be 0
2
DMA Channel Group Enable. 1=Disable; 0 = Enable.
1:0
Reserved. Must be 0.
Summary of Contents for 460GX
Page 1: ...Intel 460GX Chipset System Software Developer s Manual June 2001 Document Number 248704 001 ...
Page 20: ...Introduction 1 8 Intel 460GX Chipset Software Developer s Manual ...
Page 80: ...System Architecture 3 8 Intel 460GX Chipset Software Developer s Manual ...
Page 90: ...System Address Map 4 10 Intel 460GX Chipset Software Developer s Manual ...
Page 98: ...Memory Subsystem 5 8 Intel 460GX Chipset Software Developer s Manual ...
Page 146: ...AGP Subsystem 7 16 Intel 460GX Chipset Software Developer s Manual ...
Page 170: ...IFB Register Mapping 9 6 Intel 460GX Chipset Software Developer s Manual ...
Page 190: ...IFB Usage Considerations 10 20 Intel 460GX Chipset Software Developer s Manual ...
Page 232: ...LPC FWH Interface Configuration 11 42 Intel 460GX Chipset Software Developer s Manual ...
Page 244: ...IDE Configuration 12 12 Intel 460GX Chipset Software Developer s Manual ...
Page 258: ...Universal Serial Bus USB Configuration 13 14 Intel 460GX Chipset Software Developer s Manual ...
Page 270: ...SM Bus Controller Configuration 14 12 Intel 460GX Chipset Software Developer s Manual ...
Page 288: ...PCI LPC Bridge Description 15 18 Intel 460GX Chipset Software Developer s Manual ...
Page 294: ...IFB Power Management 16 6 Intel 460GX Chipset Software Developer s Manual ...