Intel 460GX - Manual (Page 186)

IFB Usage Considerations
10-16 Intel® 460GX Chipset Software Developer’s Manual
In the above configuration, none of the drives supports Ultra DMA. Only Non-ultra DMA and Fast
PIO support will be enabled on each drive.
10.5.10 Ultra DMA System Software Considerations
This section outlines some of the key system considerations for systems where Ultra DMA
operation is enabled.
The following components shall comprise a Ultra DMA/33 System:
1. Ultra DMA/33-capable Host IDE Controller.
2. Ultra DMA/33-capable ATA/ATAPI Devices.
3. Ultra DMA/33 Aware firmware and /or System Initialization Software.
4. Ultra DMA/33 Aware Device Driver.
Two of the aforementioned components are software based with specific requirements: Item #3,
Ultra DMA/33 Aware firmware and/or System Initialization Software; and Item #4, Ultra DMA/33
Aware Device Driver .
Ultra DMA/33 Aware firmware and/or System Initialization Software shall:
1. Identify Ultra DMA/33 capable devices and host controllers.
2. Configure Ultra DMA/33 operation for all Ultra DMA/33 capable devices and host
controllers.
3. Preserve Ultra DMA/33 configuration across reset states, restoring Ultra DMA/33 operation
(described in Item #2) as necessary.
Ultra DMA/33 Aware Device Drivers shall:
I. Provide support for PCI Bus Master IDE Operation (SFF8038i).
A. Identify system configured for PCI Bus Master IDE operation.
1. Identify PCI Bus Master IDE and Ultra DMA/33 capable devices and host
controllers.
2. Utilize PCI Bus Master IDE when it determines that Host Controller and ATA/
ATAPI devices have fulfilled device driver-specific, configuration requirements for
PCI Bus Master IDE operation.
B. Perform data transfer commands with PCI Bus Master IDE on devices, host controllers
that support PCI Bus Master IDE.
Register Type Offset Value Comments
PCI Command Register PCI 04h 0005h Ensure that bits 0 and 2 are ‘1’.
PCI Master Latency Timer PCI 0Dh System dependent
PCI Bus Master IDE Base I/O
Address PCI 20-23h System dependent Ensure that bit 0 (of register value)
is ‘1’.
IDE Timing Register 1 PCI 40-41h E377h Mode config. for Primary
IDE Timing Register 2 PCI 42-43h A103h Mode config. for Secondary
Secondary IDE Timing Register PCI 44h 0Bh
Ultra DMA Control Register PCI 48h 00h Ultra DMA is disabled for all drives.
Ultra DMA Timing Register PCI 4A-4Bh 0000h