PORTIBM PC Portable (uses same BIOS as XT) 01F0-01F6 - OPTi "Vendetta" (82C750) CHIPSET - PRIMARY IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. CONTROLLER
Note:	to unlock access to these ports, you must perform two immediately
	  successive 16-bit INs from PORTIBM PC Portable (uses same BIOS as XT) 01F1h, followed by 8-bit OUT of 03h
	  to PORTIBM PC Portable (uses same BIOS as XT) 1F2h
SeeAlso: PORTIBM PC Portable (uses same BIOS as XT) 0170h"Vendetta",PORTIBM PC Portable (uses same BIOS as XT) 01F0h"HDC 1"

01F0  RW  read cycle timing register (see #P0536)
01F1  RW  write cycle timing register (see #P0537)
01F2  RW  internal ID register (see #P0538)
01F3  RW  control register (see #P0539)
01F5  RW  strap register (see #P0540)
01F6  RW  miscellaneous register (see #P0541)


Bitfields for OPTi "Vendetta" IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller read cycle timing register:
Bit(s)	Description	(Table P0536)
 7-4	DRD# pulse width - 1 LCLKs on 16-bit IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. data register read
 3-0	recovery time between DRD# and DA2-0/DCSx# - 2 LCLKs after 16-bit IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI.
	  data register read
Notes:	if register 1F6h/176h bit 0 = 0, controls drive selected by
	  register 1F3h/173h bits 3-2
	if register 1F6h/176h bit 0 = 1, controls drive not selected by
	  register 1F3h/173h bits 3-2, if register 1F3h/173h bit 7 = 1
SeeAlso: #P0537,#P0538,#P0539


Bitfields for OPTi "Vendetta" IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller write cycle timing register:
Bit(s)	Description	(Table P0537)
 7-4	DWR# pulse width - 1 LCLKs on 16-bit IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. data register write
 3-0	recovery time between DWR# and DA2-0/DCSx# - 2 LCLKs after 16-bit IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI.
	  data register write
Notes:	if register 1F6h/176h bit 0 = 0, controls drive selected by
	  register 1F3h/173h bits 3-2
	if register 1F6h/176h bit 0 = 1, controls drive not selected by
	  register 1F3h/173h bits 3-2, if register 1F3h/173h bit 7 = 1
SeeAlso: #P0536,#P0539


Bitfields for OPTi "Vendetta" IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller internal ID register:
Bit(s)	Description	(Table P0538)
 7	controller register access disable (write-only)
 6	controller register access disable until power-down or reset
	  (write-only)
 5-2	reserved (read-only)
 1-0	reserved (11, otherwise all controller register writes blocked)
SeeAlso: #P0540


Bitfields for OPTi "Vendetta" IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller control register:
Bit(s)	Description	(Table P0539)
 7	enable 1F0h-1F1h/170h-171h and 1F6h/176h bits 5-1 cycle timing
	  set for drive not selected by 1F3h/173h bits 3-2
 6-5	reserved (read-only)
 4	(primary IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller) minimum read wait states
	0 = 2 wait states
	1 = 1 wait states
	(secondary IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller) reserved
 3	enable 1F0h-1F1h/170h-171h cycle timing set for drive 1
 2	enable 1F0h-1F1h/170h-171h cycle timing set for drive 0
 1	reserved
 0	reserved (1) (read-only)
SeeAlso: #P0540,#P0541


Bitfields for OPTi "Vendetta" IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller strap register:
Bit(s)	Description	(Table P0540)
 7	reserved (1) (read-only)
 6-5	revision number (read-only)
	11 = chip revision in PCI configuration register 08h (see #00878)
	  (see #00931)
 4	(primary IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller) DINTR state (read-only)
	(secondary IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller) SDINTR state (read-only)
 3-2	(primary IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller only) IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. device cycle time (read-only)
	value determined by PCI config register 40h bits 1-0 (see #00931)
 1	reserved (1) (read-only)
 0	(primary IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller only) PCI CLK
	0 = 33 MHz
	1 = 25 MHz
SeeAlso: #P0539,#P0541,#P0538


Bitfields for OPTi "Vendetta" IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. controller miscellaneous register:
Bit(s)	Description	(Table P0541)
 7	reserved
 6	read prefetch enable
 5-4	address setup time between DRD#/DWR# active and
	  DA2-0/DCS3#/DCS1# - 1 LCLKs
 3-1	minimum number of LCLKs between DRDY# high and DRD#/DRW# inactive - 2
 0	cycle timing register switch (1F0h/170h and 1F1h/171h)
SeeAlso: #P0539,#P0540