PORTIBM PC Portable (uses same BIOS as XT) 1C00-1CBF -  Adaptec AIC-777x EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus). SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. controller in EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus). slot 1
Notes:	Adaptec AIC-777x SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. controllers have on-board PhaseEngine SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE.
	  sequence processor which executes its instructions from the 2-Kbyte
	  sequencer RAM(Random Access Memory)	See also DRAM, SRAM.; it treats all of the CPU-addressable registers as its
	  data memory
	AIC-777x SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. controllers have special on-board RAM(Random Access Memory)	See also DRAM, SRAM. and queue registers
	  for queueing the requests sent from the drivers and BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. to the
	  PhaseEngine processor
	Adaptec AHA-284x is a VLBVESA Local Bus SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. controller based on AIC-7770; it has
	  a serial EEPROM (93C46) for storing various configuration settings
SeeAlso: PORTIBM PC Portable (uses same BIOS as XT) 0340h-035Fh"Adaptec AHA-152x",PORTIBM PC Portable (uses same BIOS as XT) xxxxh"Adaptec AIC-78xx"

+000  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. sequence control register (SCSISEQ) (see #P0600)
+001  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. transfer control register 0 (SXFRCTL0) (see #P0979)
+002  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. transfer control register 1 (SXFRCTL1) (see #P0980)
+003  R-  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. control signal read  register (SCSISIGI) (see #P0603)
+003  -W  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. control signal write register (SCSISIGO) (see #P0604)
+004  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. rate control register (SCSIRATE) (see #P0981)
+005  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. ID register (SCSIID) (see #P0982)
+006  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. latched data low register (SCSIDATL)
	  read/write causes -ACK to pulse
+007  RW  (Wide SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE.) SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. latched data high register (SCSIDATH)
	  read/write causes -ACK to pulse
+008  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. transfer count register (STCNT) (3 bytes long)
+00B  R-  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. status register 0 (SSTAT0) (see #P0607)
+00B  -W  clear SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. interrupt register 0 (CLRSINT0) (see #P0983)
+00C  R-  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. status register 1 (SSTAT1) (see #P0609)
+00C  -W  clear SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. interrupt register 1 (CLRSINT1) (see #P0610)
+00D  R-  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. status register 2 (SSTAT2) (see #P0984)
+00E  R-  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. status register 3 (SSTAT3) (see #P0612)
+00F  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. test control register (SCSITEST) (see #P0985)
+010  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. interrupt mode register 0 (SIMODE0) (see #P0616)
+011  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. interrupt mode register 1 (SIMODE1) (see #P0617)
+012  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. data bus low register (SCSIBUSL)
+013  RW  (Wide SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE.) SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. data bus high register (SCSIBUSH)
+014d R-  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE./host address register (SHADDR)
+018  RW  selection timeout timer  register (SELTIMER) (see #P0986)
+019  RW  selection/reselection ID register (SELID) (see #P0987)
+01F  RW  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. block control register (SBLKCTL) (see #P0988)
+020  RW  scratch RAM(Random Access Memory)	See also DRAM, SRAM. (64 bytes) (see #P1002)
+060  RW  sequencer control  register (SEQCTL)	(see #P0989)
+061  RW  sequencer RAM(Random Access Memory)	See also DRAM, SRAM. data register (SEQRAM)
+062w RW  sequencer address  register (SEQADDR) (see #P0990)
+064  RW  accumulator  register (ACCUM)
+065  RW  source index register (SINDEX)
+066  RW  destination index register (DINDEX)
+069  R-  all ones register (ALLONES)
	  always reads as FFh
+06A  R-  all zeros register (ALLZEROS)
	  always reads as 00h
+06B  R-  flags register (FLAGS) (see #P0991)
	  PhaseEngine processor's flags
+06C  R-  source indirect register (SINDIR)
+06D  -W  destination indirect register (DINDIR)
+06E  RW  function 1 register (FUNCTION1)
+06F  R-  "STACK"
+084  RW  board control register (BCTL) (see #P0992)
+085  RW  bus on/off time register (BUSTIME) (see #P0993)
+086  RW  bus speed register (BUSSPD) (see #P0994)
+087  RW  host control register (HCNTRL) (see #P0995)
+088d RW  host address register (HADDR)
+08C  RW  host counter register (HCNT) (3 bytes long)
+090  RW  sequence control block (SCB) pointer register (SCBPTR)
+091  RW  interrupt status register (INTSTAT) (see #P0996)
+092  R-  hard error register (ERROR) (see #P0997)
+092  -W  clear interrupt status register (CLRINT) (see #P0998)
+093  RW  DMAsee Direct Memory Access FIFO control register (DFCNTRL)  (see #P0999)
+094  R-  DMAsee Direct Memory Access FIFO status  register (DFSTATUS) (see #P1000)
+099  RW  DMAsee Direct Memory Access FIFO data register (DFDAT)
+09A  RW  SCB auto-increment register (SCBCNT) (see #P1001)
+09B  RW  queue in FIFO register (QINFIFO)
	  write places the value into the FIFO, read removes
+09C  R-  queue in count register (QINCNT)
	  number of the SCBs in the queue in
+09D  R-  queue out FIFO register (QOUTFIFO)
	  read removes the value from the FIFO
+09E  R-  queue out count register (QOUTCNT)
	  number of the SCBs in the queue out
+0A0  RW  SCB array (32 bytes) (see #P1003)
+0C0  RW  (AHA-284x) serial EEPROM control register (SEECTL) (see #P1005)
+0C1  RW  (AHA-284x) "STATUS" (see #P1006)
Notes:	the SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. latched data registers are used to transfer data on the SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE.
	  bus during automatic or manual PIO mode
	in a twin channel configuration the separate register set with the
	  addresses 00h-1Eh exists for each channel
	the SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE./host address register (SHADDR) holds the host address for the
	  byte about to be transfered on the SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. bus; it is counted up in the
	  same manner as SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. transfer count register (STCNT) is counted down
	  and should always be used to determine the address of the last byte
	  transfered since the host address register (HADDR) can be skewed by
	  read ahead
	the source/destination index registers (SINDEX/DINDEX) are used by the
	  PhaseEngine processor to indirectly address the data memory (i.e. the
	  CPU-addressable registers); the data byte addressed can be accessed
	  through the source/destination indirect registers (SINDIR/DINDIR)
	  respectively; the source index register (SINDEX) is auto-incremented
	  on each read from the source indirect register (SINDIR), while the
	  destination index register (DINDEX) is auto-incremented on each write
	  to the destination indirect register (DINDIR)
	the function 1 register (FUNCTION1) is used to convert the SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. target
	  number to the corresponding bit mask; first, bits 6-4 are written
	  with a number N (other bits seems to be "don't care"), then the
	  register is read back, giving the bit mask having bit N set and all
	  other bits cleared
	the host address register (HADDR) and the host counter register (HCNT)
	  are used for the DMAsee Direct Memory Access transfers from/to the host memory
	the SCB pointer register (SCBPTR) selects the 32-byte area of the SCB
	  RAM(Random Access Memory)	See also DRAM, SRAM. to be mapped at addresses A0h-BFh
	the queue in/out FIFO registers (QINFIO/QOUTFIFO) hold the queue of
	  the SCB pointer register's (SCBPTR) values for addressing the SCBs
	  sent by CPU(Central Processing Unit) The microprocessor which executes programs on your computer. to the PhaseEngine processor and returned to CPU(Central Processing Unit) The microprocessor which executes programs on your computer. (when
	  the associated SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. command completes) respectively; CPU(Central Processing Unit) The microprocessor which executes programs on your computer. selects
	  the SCB RAM(Random Access Memory)	See also DRAM, SRAM. area via the SCB pointer register (SCBPTR), downloads
	  prepared SCB to addresses A0h-BFh (this requeires the PhaseEngine
	  processor to be paused), then places the SCB pointer value to the
	  queue in FIFO by writing it to the respective register, from which
	  the SCB pointers can be read (and removed) in the FIFO order; the
	  PhaseEngine processor places the SCB pointer of the completed CCB
	  to the queue out FIFO by writing the respective register, and CPU(Central Processing Unit) The microprocessor which executes programs on your computer.
	  can remove it from the FIFO by reading the register


Bitfields for SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. transfer control register 0 (SXFRCTL0):
Bit(s)	Description	(Table P0979)
 7	DMAsee Direct Memory Access FIFO on? (DFON)
 6	"DFPEXP"
 5	(Ultra SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE.) Ultra SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. enable (ULTRAEN)
 4	clear SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. transfer counter (CLRSTCNT)
 3	SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. PIO enable (SPIOEN)
 2	SCAM enable (SCAMEN)
 1	clear channel (CLRCHN)
 0	reserved
SeeAlso: #P0607,#P0618,#P0620,#P0980,#P0984


Bitfields for SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. transfer control register 1 (SXFRCTL1):
Bit(s)	Description	(Table P0980)
 7	bit bucket (BITBUCKET)
 6	SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. counter wrap enable (SWRAPEN)
 5	enable SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. parity check (ENSPCHK)
 4-3	selection time-out select (STIMESEL)
	00 256 ms
	01 128 ms
	10 64  ms
	11 32  ms
 2	enable selection timer (ENSTIMER)
 1	active negation enable (ACTNEGEN)
 0	SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. terminator power enable? (STPWEN)
SeeAlso: #P0600,#P0979,#P0986


Bitfields for SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. rate control register (SCSIRATE):
Bit(s)	Description	(Table P0981)
 7	(Wide SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE.) wide transfer control (WIDEXFER)
 6-4	synchronous transfer rate (SXFR)
 3-0	synchronous offset (SOFS)
SeeAlso: #P0605,#P0984


Bitfields for SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. ID register (SCSIID):
Bit(s)	Description	(Table P0982)
 7-4	target ID (TID)
 3-0	our ID (OID)
SeeAlso: #P0606,#P0987,#P1012


Bitfields for clear SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. interrupt register 0 (CLRSINT0):
Bit(s)	Description	(Table P0983)
 7	reserved?
 6	clear selection out done (CLRSELDO)
 5	clear selection in  done (CLRSELDI)
 4	clear selection in progress (CLRSELINGO)
 3	clear SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. counter wrap (CLRSWRAP)
 2	reserved
 1	clear SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. PIO ready (CLRSPIORDY)
 0	reserved
SeeAlso: #P0600,#P0601,#P0607,#P0608,#P0616


Bitfields for SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. status register 2 (SSTAT2):
Bit(s)	Description	(Table P0984)
 7	"OVERRUN"
 6-5	reserved
 4-0	SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. FIFO count? (SFCNT)
SeeAlso: #P0979,#P0981


Bitfields for SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. test control register (SCSITEST):
Bit(s)	Description	(Table P0985)
 7-3	reserved
 2	"RQAKCNT"
 1	"CNTRTEST"
 0	"CMODE"
SeeAlso: #P0988


Bitfields for selection timeout timer register (SELTIMER):
Bit(s)	Description	(Table P0986)
 7-6	reserved
 5	"STAGE6"
 4	"STAGE5"
 3	"STAGE4"
 2	"STAGE3"
 1	"STAGE2"
 0	"STAGE1"
SeeAlso: #P0980


Bitfields for selection/reselection ID register (SELID):
Bit(s)	Description	(Table P0987)
 7-4	selecting device ID (SELID)
 3	one bit (ONEBIT)
 2-0	reserved
Note:	bit 3 is set when the selecting/reselecting device did not set its own
	  ID on the SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. bus
SeeAlso: #P0600,#P0607,#P0982



Bitfields for SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. block control register (SBLKCTL):
Bit(s)	Description	(Table P0988)
 7-6	reserved
 5	auto-flush disable (AUTOFLUSHDIS)
 4	reserved
 3	select bus (SELBUS)
	=0 select bus A
	=1 select bus B (SELBUSB)
 2	reserved
 1	"SELWIDE"
 0	reserved
Notes:	bit 1 allows for the coexistence of 8-bit and 16-bit devices on a Wide
	  SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. bus
	in a twin channel configuration addresses 00h-1Eh are gated to the
	  appropriate channel based on the value of bit 3
	bit 5 is read only on the AIC-7770 revisions prior to E


Bitfields for sequencer control register (SEQCTL):
Bit(s)	Description	(Table P0989)
 7	parity error disable (PERRORDIS)
 6	pause disable (PAUSEDIS)
 5	"FAILDIS"
 4	fast mode (FASTMODE)
 3	break address interrupt enable (BRKADRINTEN)
 2	"STEP"
 1	sequencer reset (SEQRESET)
 0	load sequencer RAM(Random Access Memory)	See also DRAM, SRAM. (LOADRAM)
Notes:	setting bit 1 causes the sequencer to be paused; the sequencer address
	  register is reset to 0
	bit 7 should be reset while loading the sequencer RAM(Random Access Memory)	See also DRAM, SRAM.; after loading
	  is complete, bit 0 should be cleared before changing the sequencer
	  address register (SEQADDR) to avoid sequencer RAM(Random Access Memory)	See also DRAM, SRAM. parity errors
SeeAlso: #P0990,#P0996,#P0997,#P0998,#P1014


Bitfields for sequencer address register (SEQADDR):
Bit(s)	Description	(Table P0990)
 15-9	reserved
 8-0	sequencer RAM(Random Access Memory)	See also DRAM, SRAM. address
Notes:	bits 8-0 contain the address of a DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address. in the sequencer RAM(Random Access Memory)	See also DRAM, SRAM.; it points
	  to the next instruction to be execute or load into RAM(Random Access Memory)	See also DRAM, SRAM.
	setting bit 1 in the sequencer control register (SEQCTL) resets this
	  address to 0
	when the PhaseEngine processor is paused, the sequencer address can be
	  altered and a sequencer program can be loaded by writing it, byte by
	  byte, to the sequencer RAM(Random Access Memory)	See also DRAM, SRAM. data register (SEQRAM); the address is
	  auto-incremented after the high BYTE of each DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address. is loaded
SeeAlso: #P0989,#P1014


Bitfields for flags register (FLAGS):
Bit(s)	Description	(Table P0991)
 7-2	reserved
 1	zero  flag (ZERO)
 0	carry flag (CARRY)
SeeAlso: #P1014


Bitfields for board control register (BCTL):
Bit(s)	Description	(Table P0992)
 7-4	reserved
 3	"ACE"
 2-1	reserved
 0	enable board (ENABLE)
Note:	bit 3 is somehow related to the support for the external processors


Bitfields for bus on/off time register (BUSTIME):
Bit(s)	Description	(Table P0993)
 7-4	bus off time (BOFF)
	in 4 BCLK cycle units?
 3-0	bus on	time (BON)
SeeAlso: #P0994,#P1002


Bitfields for bus speed register (BUSSPD):
Bit(s)	Description	(Table P0994)
 7-6	DMAsee Direct Memory Access FIFO threshold (DFTHRSH)
	11 100?
 5-3	"STBOFF"
 2-0	"STBON"
SeeAlso: #P0993,#P0999,#P1000,#P1002


Bitfields for host control register (HCNTRL):
Bit(s)	Description	(Table P0995)
 7	reserved
 6	power down (POWRDN)
 5	reserved
 4	software interrupt (SWINT)
 3	IRQ(Interrupt ReQuest) A hardware line connected to the interrupt controller chip which signals that a CPU interrupt should be generated. mode select (IRQMS)
	=0 level-sensitive
	=1 edge-triggered
 2	pause sequencer (PAUSE)
 1	interrupt enable (INTEN)
 0	chip reset (CHIPRST)
Notes:	bit 0 is self-clearing (though on some AIC-7771 based boards it stucks
	  set, and must be manually cleared)
	set bit 2 to pause the sequencer, then poll the register until this bit
	  reads as 1 indicating that the sequencer has actually stopped; the
	  sequencer can disable pausing for critical sections through bit 6 of
	  the sequencer control register (SEQCTL)
SeeAlso: #P0989,#P1014


Bitfields for interrupt status register (INTSTAT):
Bit(s)	Description	(Table P0996)
 7-4	sequencer status
	0000 unknown SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. bus phase (BAD_PHASE)
	0001 sending MESSAGE REJECT (SEND_REJECT)
	0010 no IDENTIFY after reconnect (NO_IDENT)
	0011 no command match for reconnect (NO_MATCH)
	0100 SYNCRONOUS DATA TRANSFER REQUEST (SDTR) message received (SDTR_MSG)
	0101 WIDE DATA TRANSFER REQUEST (WDTR) message received (WDTR_MSG)
	0110 MESSAGE REJECT received (REJECT_MSG)
	0111 bad status from target (BAD_STATUS)
	1000 residual byte count non-zero (RESIDUAL)
	1001 sent ABORT TAG message (ABORT_TAG)
	1010 awaiting message
	1011 immediate command completed (IMMEDDONE)
	1100 message buffer busy (MSG_BUFFER_BUSY)
	1101 MESSAGE IN phase mismatch (MSGIN_PHASEMIS)
	1110 data overrun (DATA_OVERRUN)
 3	break address interrupt (BRKADRINT)
 2	SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. interrupt (SCSIINT)
 1	command complete interrupt (CMDCMPLT)
 0	sequencer interrupt (SEQINT)
Notes:	the PhaseEngine processor can set bit 0 to interrupt the CPU(Central Processing Unit) The microprocessor which executes programs on your computer. requesting
	  some service from it; an interrupt reason is passed in bits 7-4
	the PhaseEngine processor sets bit 1 after placing a completed SCB into
	  the queue out FIFO
	setting bit 0 pauses the PhaseEngine processor; it needs unpausing via
	  resetting bit 2 of the host control register (HCNTRL)
SeeAlso: #P0986,#P0993,#P0995,#P1014


Bitfields for hard error register (ERROR):
Bit(s)	Description	(Table P0997)
 7-4	reserved
 3	sequencer RAM(Random Access Memory)	See also DRAM, SRAM. parity error (PARERR)
 2	illegal opcode in sequencer program (ILLOPCODE)
 1	illegal sequencer address referenced (ILLSADDR)
 0	illegal host access (ILLHADDR)
Note:	usually a full board reset is required after detecting a hard error
SeeAlso: #P1014


Bitfields for clear interrupt status register (CLRINT):
Bit(s)	Description	(Table P0998)
 7-4	reserved
 3	clear break address interrupt (CLRBRKADRINT)
 2	clear SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. interrupt (CLRSCSIINT)
 1	clear command complete interrupt (CLRCMDINT)
 0	clear sequencer interrupt (CLRSEQINT)
SeeAlso: #P0986,#P0991,#P1014


Bitfields for DMAsee Direct Memory Access FIFO control register (DFCNTRL):
Bit(s)	Description	(Table P0999)
 7	reserved
 6	"WIDEODD"
 5	SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. enable (SCSIEN)
 4	SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. DMAsee Direct Memory Access enable? (SDMAEN)
 3	host DMAsee Direct Memory Access enable? (HDMAEN)
 2	"DIRECTION"
	=0 SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. to host
	=1 host to SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE.
 1	FIFO flush (FIFOFLUSH)
 0	FIFO reset (FIFORESET)
Notes:	this register allows the PhaseEngine processor to control DMAsee Direct Memory Access transfers
	  from/to host memory
	bits 3 and 4 clear automatically when host and SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. DMAsee Direct Memory Access is complete
	  respectively
SeeAlso: #P0994,#P1000


Bitfields for DMAsee Direct Memory Access FIFO status register (DFSTATUS):
Bit(s)	Description	(Table P1000)
 7-6	reserved
 5	"DWORDEMP"
 4	"MREQPEND"
 3	host DMAsee Direct Memory Access done (HDONE)
 2	DMAsee Direct Memory Access FIFO threshold? (DFTHRESH)
 1	FIFO full  (FIFOFULL)
 0	FIFO empty (FIFOEMP)
SeeAlso: #P0994,#P0999


Bitfields for SCB auto-increment register (SCBCNT):
Bit(s)	Description	(Table P1001)
 7	SCB auto-increment (SCBAUTO)
 6-5	reserved
 4-0	SCB counter (SCBCNT)
Note:	this register allows CPU(Central Processing Unit) The microprocessor which executes programs on your computer. to quickly upload/download the SCBs to/from
	  the SCB RAM(Random Access Memory)	See also DRAM, SRAM.; if bit 7 is set any reference to addresses A0h-BFh post-
	  increments bits 4-0 of this register containing the offset into the
	  SCB array which is to be accessed next; on the AHA-284x only 8-bit
	  transfers can be used
SeeAlso: #P1003


Format of the scratch RAM(Random Access Memory)	See also DRAM, SRAM.:
Offset	Size	Description	(Table P1002)
 00h 16 BYTEs	target scratch (TARG_SCRATCH) (see #9025)
 10h	WORD	channel A Ultra SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. enable (ULTRA_ENB_A)
		bit N if set means Ultra SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. transfers are enabled for the
		  target ID N
 10h	BYTE	rejected byte (REJBYTE)
 11h	BYTE	channel B Ultra SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. enable (ULTRA_ENB_B)
		bit N if set means Ultra SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. transfers are enabled for the
		  target ID N
 11h	BYTE	rejected byte extended (REJBYTE_EXT)
 11h	BYTE	rejected byte (REJBYTE)
 12h	BYTE	channel A disable disconnect (DISC_DSB_A)
 13h	BYTE	channel B disable disconnect (DISC_DSB_B)
 14h	BYTE	length of pending message (MSG_LEN)
 15h  8 BYTEs	outgoing message (MSG0-MSG7)
 15h	BYTE	pending	 message flag (MSG_FLAGS)
 16h	BYTE	length of pending message (MSG_LEN)
 17h  ? BYTEs	outgoing message body (MSG_START)
 1Dh	BYTE	parameters for DMAsee Direct Memory Access logic (DMAPARAMS) (see #P0999)
 1Dh	BYTE	last phase (LASTPHASE)
 1Eh	BYTE	"SEQ_FLAGS"
		bit 7: "RESELECTED"
		bit 6: "IDENTIFY_SEEN"
		bit 5: "TAGGED_SCB"
		bit 4: data phase seen (DPHASE)
		bit 3: reserved
		bit 2: page SCBs (PAGESCBS)
		bit 1: "WIDE_BUS"
		bit 0: "TWIN_BUS"
 1Eh	BYTE	"ARG_1"
		bit 0: "MAXOFFSET"
 1Fh	BYTE	saved target/channel/LUN (SAVED_TCL)
		bits 7-4: target ID
		bit 3: channel (0=A, 1=B)
		bits 2-0: LUN
 1Fh	BYTE	"RETURN_1"
		00h do nothing
		10h SCB paged in (SCB_PAGEDIN)
		20h send MESSAGE REJECT message (SEND_REJ)
		40h send REQUEST SENSE	command (SEND_SENSE)
		60h send SYNCHRONOUS DATA TRANSFER REQUEST message (SEND_SDTR)
		80h send WIDE DATA TRANSFER REQUEST message (SEND_WDTR)
 20h	BYTE	scatter/gather count (SG_COUNT)
 20h	BYTE	"SIGSTATE"
 21h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	scatter/gather next segment pointer (SG_NEXT)
 21h	BYTE	parameters for DMAsee Direct Memory Access logic (DMAPARAMS) (see #P0999)
 22h	BYTE	scatter/gather count (SG_COUNT)
 23h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	scatter/gather next segment pointer (SG_NEXT)
 25h	BYTE	waiting SCB list head (WAITING_SCBH)
 26h	BYTE	saved link pointer (SAVED_LINKPTR)
 27h	BYTE	saved SCB pointer (SAVED_SCBPTR)
 27h	BYTE	SCB count (SCBCOUNT)
		number of SCBs supported in hardware
 28h	BYTE	last phase (LASTPHASE) (see #9003)
		bit 7: -C/D input (CDI)
		bit 6: -I/O input (IOI)
		bit 5: -MSG input (MSGI)
		bits 4-0: reserved
 28h	BYTE	negative SCB count (COMP_SCBCOUNT)
 29h	BYTE	extended message length (MSGIN_EXT_LEN)
 29h	BYTE	queue count mask (QCNTMASK)
		works around a bug in AIC-7850
 2Ah	BYTE	extended message opcode (MSGIN_EXT_OPCODE)
 2Ah	BYTE	"FLAGS"
		bit 7: "RESELECTED"
		bit 6: IDENTIFY message seen (IDENTIFY_SEEN)
		bit 5: "SELECTED"
		bit 4: data phase seen (DPHASE)
		bit 3: reserved
		bit 2: page SCBs (PAGESCBS)
		bit 1: wide bus	 (WIDE_BUS)
		bit 0: twin bus	 (TWIN_BUS)
 2Bh  3	BYTEs	extended message tail bytes (MSGIN_EXT_BYTES)
 2Bh	BYTE	saved target/channel/LUN (SAVED_TCL)
		bits 7-4: target ID
		bit 3: channel (0=A, 1=B)
		bits 2-0: LUN
 2Ch	WORD	channel A active targets (ACTIVE_A)
		bit N is set if there's untagged SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. command currently active
		  on the target ID N
 2Ch	BYTE	"ARG_1" or "RETURN_1"
 2Dh	BYTE	channel B active targets (ACTIVE_B)
		bit N is set if there's untagged SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. command currently active
		  on the target ID N
 2Dh	BYTE	"ARG_2"
 2Eh	BYTE	disconnected SCB list head (DISCONNECTED_SCBH)
 2Eh	BYTE	waiting SCB list head (WAITING_SCBH)
 2Eh	BYTE	signal state (SIGSTATE)
 2Fh	BYTE	free SCB list head (FREE_SCBH)
		disconnected SCB list head (DISCONNECTED_SCBH)
 2Fh	BYTE	"NEEDSDTR"
		bit N if set means that the synchronous data transfer needs to
		  be negotiated with the target ID N
 30h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	"HSCB_ADDR"
 30h	BYTE	saved link pointer (SAVED_LINKPTR)
 31h	BYTE	saved SCB  pointer (SAVED_SCBPTR)
 32h	WORD	channel A Ultra enable (ULTRA_ENB)
		bit N if set means Ultra SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. transfers are enabled for the
		  target ID N
 33h	BYTE	channel B Ultra enable (ULTRA_ENB_B)
		bit N if set means Ultra SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. transfers are enabled for the
		  target ID N
 34h	BYTE	"CUR_SCBID"
 35h	BYTE	"CMDOUTCNT"
		count of commands placed in the out FIFO
 36h	BYTE	SCB count (SCBCOUNT)
		number of SCBs supported in hardware
 36h	BYTE	"ARG_1" or "RETURN_1"
		bit 7: "SEND_MSG"
		bit 6: "SEND_SENSE"
		bit 5: "SEND_REJ"
		bits 4-0: reserved
 37h	WORD	channel A active targets (ACTIVE_A)
		bit N is set if there's untagged SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. command currently active
		  on the target ID N
 39h	BYTE	reserved
 3Ah	WORD	SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. configuration (SCSICONF)
		bits 15-12: reserved?
		bits 11-8: (Wide SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE.) our ID (see #P0982)
		bit 7: (AIC-777x) enable SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. low byte termination (see #P1011)
		bit 6: enable SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. bus reset at power up (RESET_SCSI)
			 (see #P1011)
		bit 5: enable SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. parity check (ENSPCHK) (see #P0980)
		bits 4-3: selection time-out select (STIMESEL) (see #P0980)
		bits 2-0: our ID (see #P0982)
 3Bh	BYTE	channel B SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. configuration
		see bits 7-0 above
 3Ch	BYTE	"INTDEF"
		bits 7-4: reserved?
		bits 3-0: IRQ(Interrupt ReQuest) A hardware line connected to the interrupt controller chip which signals that a CPU interrupt should be generated. number (IRQ9..IRQ12, IRQ14, and IRQ15 are valid)
 3Dh	BYTE	host configuration (HOSTCONF)
		bits 7-6: DMAsee Direct Memory Access FIFO threshold (DFTHRSH) (see #9038)
		bits 5-2: bus off time (BOFF) (see #9037)
		bits 1-0: reserved?
 3Eh	BYTE	reserved
 3Fh	BYTE	(AIC-7771) BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. control (BIOSCTRL)
		bits 5-4: BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. mode (BIOSMODE)
			  11 BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. disabled (BIOSDISABLED)
		bit 3: channel B is primary (CHANNEL_B_PRIMARY)
Notes:	the scratch RAM(Random Access Memory)	See also DRAM, SRAM. is used for passing information between the driver and
	  BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. and the code running on the PhaseEngine processor; it serves as
	  a working memory for the PhaseEngine processor as well
	location definitions overlap due to various sources giving different
	  scratch RAM(Random Access Memory)	See also DRAM, SRAM. layouts
	the PhaseEngine processor uses "ARG_1" and "ARG_2" to pass parameters
	  to the drivers and BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. during sequencer interrupts; "RETURN_1" is used
	  to return results from the drivers and BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. to the PhaseEngine code
	the PhaseEngine processor uses SCB pointer register's (SCBPTR) values
	  to link SCB in the lists, with value FFh indicating the end of list
SeeAlso: #9047,#9048


Format of the SCB array:
Offset	Size	Description	(Table P1003)
 00h	BYTE	"SCB_CONTROL"
		bit 7: need WDTR message (NEEDWDTR) or
		       "MK_MESSAGE"
		bit 6: disconnect enable (DISCENB)
		bit 5: tagging enable (TAG_ENB)
		bit 4: need SDTR message (NEEDSDTR) or
		       "MUST_DMAUP_SCB"
		bit 3: "ABORT_SCB"
		bit 2: "DISCONNECTED"
		bits 1-0: command tag type (SCB_TAG_TYPE)
 01h	BYTE	target/channel/LUN (SCB_TCL)
		bits 7-4: target ID
		bit 3: channel (0=A, 1=B)
		bits 2-0: LUN
 02h	BYTE	target status (SCB_TARGET_STATUS)
		SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. status byte
 03h	BYTE	scatter/gather count (SCB_SGCOUNT)
 04h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	scatter/gather pointer (SCB_SGPTR)
 08h	BYTE	residual scatter/gather count (SCB_RESID_SGCNT)
 09h  3 BYTEs	residual data count (SCB_RESID_DCNT)
 0Ch	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	data pointer (SCB_DATAPTR)
 10h  3 BYTEs	data count (SCB_DATACNT)
 13h	BYTE	next linked SCB index (SCB_LINKED_NEXT)
 14h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	command pointer (SCB_CMDPTR)
 18h	BYTE	command length (SCB_CMDLEN)
 19h	BYTE	command tag (SCB_TAG)
 1Ah	BYTE	next SCB index (SCB_NEXT)
 1Bh	BYTE	previous SCB index (SCB_PREV)
 1Ch  2	WORDs	busy targets (SCB_BUSYTARGETS)
		bit N is set if there's untagged SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. command currently active
		  on the target ID N
SeeAlso: #P1004,#P1014


Format of the scatter/gather segment:
Offset	Size	Description	(Table P1004)
 00h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	physical address
 04h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	length
SeeAlso: #P1003,#P1014


Bitfields for AHA-284x serial EEPROM control register (SEECTL):
Bit(s)	Description	(Table P1005)
 7-3	reserved
 2	chip select (CS)
 1	clock (CK)
 0	data out (DO)
Notes:	93C46 serial EEPROM chips have 1024 bits organized into 64 16-bit
	  words and use 6 bits to address each word
	only the first 32 words of serial EEPROM are used by the Adaptec BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly.
	bits 2-0 are connected to the chip select, clock, and data out pins of
	  the serial EEPROM respectively
	bit 1 must be pulled high and then low for a minimum of 750 and 250 ns
	  to provide clocking for the EEPROM chip
	bit 1 going from low to high causes the EEPROM chip to sample the data
	  out pin and initiates the next bit to be sent through the data in pin
	bit 2 must be set for a minimum of 1 mcs with the bit 1 goig high and
	  then low for the EEPROM chip to be selected; then the instruction can
	  be sent to the EEPROM chip
	instruction can be terminated by taking the EEPROM chip select pin low,
	  with the bit 1 going high and low
SeeAlso: #P1006,#P1007,#P1008


Bitfields for AHA-284x "STATUS" register:
Bit(s)	Description	(Table P1006)
 7	EEPROM timer fired? (EEPROM_TF)
 6-5	"BIOS_SEL"
 4-1	"ADSEL"
 0	data in (DI)
Notes:	bit 0 is connected to the data in pin of the serial EEPROM; it can be
	  read after the clock pin goes from high to low
	bit 7 is cleared after a read from the serial EEPROM control register
	  (SEECTL) and goes high 800 ns later
SeeAlso: #P1005,#P1007,#P1008


(Table P1007)
Values for the 93C46 serial EEPROM instructions:
Opcode	   Function  Parameter	Description
0000xxxxb  EWDS	     -		disable all programming instructions
0001xxxxb  WRAL	     D15..D0	write to all registers
0010xxxxb  ERAL	     -		erase all registers
0011xxxxb  EWEN	     -		write enable
				must precede all programming modes
01AAAAAAb  WRITE     D15..D0	write register with address A5..A0
10AAAAAAb  READ	     -		read registers starting with address A5..A0
11AAAAAAb  ERASE     -		erase register with address A5..A0
Notes:	while the chip select pin remains high an instuction and the optional
	  parameter word can be clocked in MSB first, beginning with the start
	  bit of 1
	16-bit parameter and data words are transferred MSB first, beginning
	  with the start bit of 0
SeeAlso: #P1005,#P1006


Format of the AHA-284x serial EEPROM:
Address	Size	Description	(Table P1008)
 00h  16 WORDs	SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. ID configuration (see #P1009)
 10h	WORD	BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. control (see #P1011)
 11h	WORD	host adapter control (see #P1012)
 12h	WORD	bus release time / host adapter ID (see #P1013)
 13h	WORD	maximum targets (see #P1014)
 14h  11 WORDs	reserved
 1Fh	WORD	checksum
SeeAlso: #P1005,#P1006


Bitfields for the serial EEPROM SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. ID configuration word:
Bit(s)	Description	(Table P1009)
 15-11	reserved
 10	report even if not found (CFRNFOUND)
 9	include in BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. scan (CFINCBIOS)
 8	send START UNIT SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. command (CFSTART)
 7-6	reserved
 5	(Wide SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE.) wide bus device (CFWIDEB)
 4	enable disconnection (CFDISC)
 3	enable synchronous transfer (CFSYNCH)
 2-0	synchronous transfer rate (CFXFER)
SeeAlso: #P0605,#P1008


Bitfields for the serial EEPROM BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. control word:
Bit(s)	Description	(Table P1011)
 15-6	reserved
 5	extended translation (CFEXTEND)
 4	support more than 2 drives (CFSM2DRV)
 3	reserved
 2	BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. enabled (CFBIOSEN)
 1	support removable drives for boot only (CFSUPREMB)
 0	support all removable drives (CFSUPREM)
SeeAlso: #P1008


Bitfields for the serial EEPROM host adapter control word:
Bit(s)	Description	(Table P1011)
 15-7	reserved
 6	reset SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. bus at IC initialization (CFRESETB)
 5	SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. low byte termination (CFSTERM)
	=0 disable
	=1 enable
 4	SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. parity (CFSPARITY)
	=0 disable
	=1 enable
 3-2	FIFO threshold (CFFIFO)
 1-0	selection timeout (CFSELTO)
SeeAlso: #P0600,#P0980,#P0994,#P1008


Bitfields for the serial EEPROM bus release time / host adapter ID word:
Bit(s)	Description	(Table P1012)
 15-8	bus release time (CFBRTIME)
 7-4	reserved
 3-0	host adapter SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. ID (CFSCSIID)
SeeAlso: #P0982,#P0989,#P1007


Bitfields for the serial EEPROM maximum targets word:
Bit(s)	Description	(Table P1013)
 15-8	reserved
 7-0	maximum targets (CFMAXTARG)
SeeAlso: #P1007


Bitfields for the PhaseEngine SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer.	A host adapter connects the SCSI bus to the computer's own bus.  See also ESDI, IDE. sequence processor instruction:
Bit(s)	Description	(Table P1014)
 31-29	reserved (0)
 28-25	opcode
	0000 OR	 dest,imm[,src] [RET]
	     MVI dest,imm [RET]
	0001 AND dest,imm[,src] [RET]
	     MOV dest,src [RET]
	     CLR dest [RET]
	     NOP [RET]
	     RET
	0010 XOR dest,imm[,src] [RET]
	     NOT dest [RET]
	0011 ADD dest,imm[,src] [RET]
	     INC dest[,src] [RET]
	     DEC dest[,src] [RET]
	     CLC [dest[,imm]] [RET]
	     STC dest [RET]
	0100 ADC dest,imm[,src] [RET]
	0101 SHL/SHR/ROL/ROR dest,[src,]imm [RET]
	1000 OR	 src,imm JMP addr
	     MOV src JMP addr
	     MVI imm JMP addr
	     JMP addr
	1001 OR	 src,imm JC addr
	     MOV src JC addr
	     MVI imm JC addr
	     JC addr
	1010 OR	 src,imm JNC addr
	     MOV src JNC addr
	     MVI imm JNC addr
	     JNC addr
	1011 OR	 src,imm CALL addr
	     MOV src CALL addr
	     MVI imm CALL addr
	     CALL addr
	1100 CMP  src,imm JNE addr
	1101 TEST src,imm JNZ addr
	1110 CMP  src,imm JE  addr
	1111 TEST src,imm JZ  addr
	others reserved
 24-16	(jump instructions) instruction address
 24	(non-jump instructions) return flag
 23-16	(non-jump instructions) destination register address
 15-8	source register address
 7-0	(shift instructions) shift control (see #P1015)
	(other instructions) immediate data
	if 0 accumulator register (ACCUM) is used instead
Notes:	the jump instructions with the OR/MOV/MVI prefixes implicitly use the
	  source index register (SINDEX) as destination
SeeAlso: #P0989,#P0990,#P0991,#P0995,#P0996,#P0997,#9042


Bitfields for the PhaseEngine shift control:
Bit(s)	Description	(Table P1015)
 7	clear all bits?
 6-4	number of bits to shift the AND mask (FFh)
 3	=0 shift the AND mask left
	=1 shift the AND mask right
 2-0	number of bits to rotate the source left
Notes:	the 8-bit source seems to be rotated left and then AND'ed with the mask
	  (FFh) which is shifted left or right prior to AND'ing in order to
	  perform all kinds of the shift/rotate instructions
	bit 7 is set (and bits 6-4 equal 7) if the shift count is greater than
	  7 specified for the SHL/SHR instructions