LPC/FWH Interface Configuration
11-18
Intel® 460GX Chipset Software Developer’s Manual
11.2.1.6
Ds–Dma Status Register (I/O)
I/O Address:
Channels 0-3–08h; Channels 4-7–0D0h
Default Value:
00h
Attribute:
Read Only
Each DMA controller has a read-only DMA Status Register that indicates which channels have
reached terminal count and which channels have a pending DMA request.
11.2.1.7
DBADDR–DMA Base and Current Address Registers (I/O)
I/O Address:
DMA Channel 0–000h
DMA Channel 4–0C0h
DMA Channel 1–002h
DMA Channel 5–0C4h
DMA Channel 2–004h
DMA Channel 6–0C8h
DMA Channel 3–006h
DMA Channel 7–0CCh
Default Value:
Undefined (CPURST or Master Clear)
Attribute:
Read/Write
This Register works in conjunction with the Low Page Register. After an auto-initialization, this
register retains the original programmed value. Auto-initialize takes place after a TC. The address
register is automatically incremented or decrement after each transfer. This register is read/written
in successive 8-bit bytes. The programmer must issue the Clear Byte Pointer Flip-Flop command to
reset the internal byte pointer and correctly align the write prior to programming the Current
Address Register. Auto-initialize takes place only after a TC.
Bit
Description
7:4
Channel Request Status. When a valid DMA request is pending for a channel (on its DREQ
signal line), the corresponding bit is set to 1. When a DMA request is not pending for a
particular channel, the corresponding bit is set to 0. The source of the DREQ may be hardware
or a software request. Note that channel 4 does not have DREQ or DACK lines, so the
response for a read of DMA2 status for channel 4 is irrelevant.
Bit Channel
4 0
5 1 (5)
6 2 (6)
7 3 (7)
3:0
Channel Terminal Count Status. 1=TC is reached; 0=TC is not reached.
Bit Channel
0 0
1 1 (5)
2 2 (6)
3 3 (7)
Bit
Description
15:0
Base and Current Address [15:0]. These bits represent address bits [15:0] used when
forming the 24-bit address for DMA transfers.
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 ...