Identify Device Information Used For Determining Multi/Single Word Dma Drive Capabilities - Intel 460GX Software Developer’s Manual

IFB Usage Considerations
The drive's multi word DMA mode capability and current configuration are specified in the
IDENTIFY_DRIVE buffer, Words 63 and 65 Software must first check to see that the Words 64-70
are valid before determining the drive's multi word DMA drive capability.
The drive's single word DMA mode capability and current configuration are specified in the
IDENTIFY_DRIVE buffer, Word 62.
Table 10-3. Identify Device Information Used for Determining Multi/Single Word DMA Drive
Capabilities
Capability
PIO, DMA
DMA
DMA
DMA
DMA
DMA
To determine the drive's best DMA capability ensure that the drive reports the capability and is
able to transfer at the target cycle time, as shown in
10-6
Word Offset Bits
53 1
62 10:8
62 2:0
63 10:8
63 2:0
65 15:0
Intel® 460GX Chipset Software Developer's Manual
Field
Field Validity
0: the fields reported in words 64-70 are not valid
1: the fields reported in word 64-70 are valid
Single Word DMA Modes Active
bit 10: 1: Single Word DMA Mode 2 is active
0: Single Word DMA Mode 2 is not active
bit 9: 1: Single Word DMA Mode 1 is active
0: Single Word DMA Mode 1 is not active
bit 8: 1: Single Word DMA Mode 0 is active
0: Single Word DMA Mode 0 is not active
Single Word DMA Modes Supported
bit 2: 1: Single Word DMA Mode 2 is supported
0: Single Word DMA Mode 2 is not supported
bit 1: 1: Single Word DMA Mode 1 is supported
0: Single Word DMA Mode 1 is not supported
bit 0: 1: Single Word DMA Mode 0 is supported
0: Single Word DMA Mode 0 is not supported
Multi Word DMA Modes Active
bit 10: 1: Multi Word DMA Mode 2 is active
0: Multi Word DMA Mode 2 is not active
bit 9: 1: Multi Word DMA Mode 1 is active
0: Multi Word DMA Mode 1 is not active
bit 8: 1: Multi Word DMA Mode 0 is active
0: Multi Word DMA Mode 0 is not active
Multi Word DMA Modes Supported
bit 2: 1: Multi Word DMA Mode 2 is supported
0: Multi Word DMA Mode 2 is not supported
bit 1: 1: Multi Word DMA Mode 1 is supported
0: Multi Word DMA Mode 1 is not supported
bit 0: 1: Multi Word DMA Mode 0 is supported
0: Multi Word DMA Mode 0 is not supported
Minimum Multi Word DMA Transfer Cycle Time per
Word
Table 10-4.