Field Name Bits Default Description
IDE Internal PCI master
request selection
0 0b Select number of delay cycles on internal PCI master request
0: delay two PCI cycles
1: delay three PCI cycles
IDE PCI request control 1 0b Control PCI request deassertion timing at PCI retry cycle.
0: allows IDE’s PCI request to be deasserted one cycle early.
1: PCI request will be deasserted one cycle late.
Reserved 5:2 0h Reserved. Always read as 0’s
IDE Fast sampling
Enable
6 1b Enable fast sampling on IORDY (DDMARDY#) port
0: Use regular IDE clock to sample
1: Use either (50/66MHz) sampling IORDY (DDMARDY#) port
at ultra DMA mode
Reserved 7 0b Reserved.
Explicit/Implicit prefetch
Switch
8 0b Control implicit or explicit prefetch function
0: Explicit prefetch is enabled
1: Implicit prefetch is enabled
Recommendation is to have it reset to 0 for better bus
efficiency
Reserved 12:9 0h Reserved
MSI capability visible
control
13 0b When this bit is set MSI capability will be visible.
Reserved 14 0b Reserved
MSI_MME[0] hidden
control bit
15 0b Control Multiple/Single Message Enable
0: Only 1 message allocated
1: 2 messages allocated
IDE Internal Control Register: This register can enable internal PCI request timing and different IDE arbitration
schemes.
IDE Misc. Control - RW- 32 bits - [PCI_Reg:64h] Field Name Bits Default Description
Reserved 0 0b Reserved.
IDE Internal Logic Reset 1 0b IDE internal reset. This reset follows IDE PLL reset. Software
control the duration between both resets.
Primary Channel Tri-
state Mode
2 0b Primary channel tri-state mode if it is set to 1.
Reserved 3 0b Reserved. Always read as 0’s.
Preliminary Buffer
Threshold Control
6:4 001b Programmable threshold control for preliminary buffer.
Reserved 31:7 00E0258
h
Reserved. Do not use
IDE Misc. Control Register: This register specifies IDE tri-state channel enable, and preliminary buffer threshold
control.
IDE MSI Programmable Weight - RW- 8 bits - [PCI_Reg:68h] Field Name Bits Default Description
MSI Interrupt Weight 5:0 01h MSI programmable interrupt weight.
Reserved 7:6 0h Reserved. Always wired as 0’s.
IDE MSI Programmable Weight Register: This register specifies MSI weight.