Ifb Timing Settings; Ifb Drive Mode Based On Dma/Pio Capabilities - Intel 460GX Software Developer’s Manual

10.5.6

IFB Timing Settings

10.5.6.1 DMA/PIO Timing Settings
In Table 10-7, 'x'=depends on the type of drive installed, '1'=enabled, and '0'=disabled.
Ultra DMA mode settings are completely independent of the following timings.
Table 10-7. IFB Drive Mode Based on DMA/PIO Capabilities
Drive's Best Drive's Best
DMA PIO
Capability Capability
N/A PIO0/1/
(DMA not Compatible
supported)
N/A PIO2
(DMA not
supported)
N/A PIO3
(DMA not (w/IORDY)
supported)
N/A PIO4
(DMA not (w/IORDY)
supported)
Single Word PIO0/1/
DMA Mode 2 Compatible
Single Word PIO2
DMA Mode 2
Single Word PIO3
DMA Mode 2 (w/IORDY)
Single Word PIO4
DMA Mode 2 (w/IORDY)
Multi Word PIO0/1/
DMA Mode 1 Compatible/
PIO2
Multi Word PIO3
DMA Mode 1 (w/IORDY)/
PIO4
(w/IORDY)
Multi Word PIO0/1/
DMA Mode 2 Compatible/
PIO2
Multi Word PIO3
DMA Mode 2 (w/IORDY)
Multi Word PIO4
DMA Mode 2 (w/IORDY)
a. Configurations where a drive reports a PIO speed much slower than its reported DMA speed require the DMA Timing Enable Only Select bit to be
Enabled.
Intel® 460GX Chipset Software Developer's Manual
Fast PIO
Non Ultra DMA
Supported?
IFB Supported?
Best PIO
Timing
Mode >=
Mode Mode is {SW2,
Best DMA
MW1, MW2}
Mode
Mode 0 No No
Mode 2 Yes No
Mode 3 Yes No
Mode 4 Yes No
Mode 2 No (special Yes
config.
needed)
Mode 2 Yes No
Mode 2 Yes No
Mode 2 Yes No
Mode 3 No (special Yes
config.
needed)
Mode 3 Yes No
Mode 4 No (special Yes
config.
needed)
Mode 3 Yes No
Mode 4 Yes No
DMA
Timing Prefetch and
Best DMA Enable
Only Select Enable Select
a
Disabled Enabled
(if fixed disk)
Disabled Enabled
(if fixed disk)
Disabled Enabled
(if fixed disk)
Disabled Enabled
(if fixed disk)
Enabled Enabled
(if fixed disk)
Disabled Enabled
(if fixed disk)
Disabled Enabled
(if fixed disk)
Disabled Enabled
(if fixed disk)
Enabled Enabled
(if fixed disk)
Disabled Enabled
(if fixed disk)
Enabled Enabled
(if fixed disk)
Disabled Enabled
(if fixed disk)
Disabled Enabled
(if fixed disk)
IFB Usage Considerations
IORDY
Fast Timing
Sample
Posting Bank Drive
Point Enable
Select
Disabled Disabled
Depends on Enabled
Drive
Enabled Enabled
Enabled Enabled
Depends on Enabled
Drive
Depends on Enabled
Drive
Depends on Enabled
Drive
Depends on Enabled
Drive
Enabled Enabled
Enabled Enabled
Enabled Enabled
Enabled Enabled
Enabled Enabled
Select
10-9