T
T
TS
S
S3
3
32
2
2M
M
M~
~
~1
1
1G
G
GC
C
CF
F
F8
8
80
0
0
80X CompactFlash Card
Transcend Information Inc.
41
5.5.3 Feature Register (Address - 1F1h[171h]; Offset 1, 0Dh Write Only)
This register provides information regarding features of the CompactFlash Storage Card that the h ost can utilize. This
register is also accessed in PC Card modes on data bits D15-D8 during a write operation to Of fset 0 with -CE2 low and
-CE1 high.
5.5.4 Sector Count Register (Address - 1F2h[172h]; Offset 2)
This register contains the numbers of sectors of data requested to be transferred on a read or write operation between the
host and the CompactFlash Storage Card. If the value in this register is zero, a count of 256 sectors is specified. If the
command was successful, this register is zero at command completion. If not suc cessfully completed, the register
contains the number of sectors that need to be transferred in order t o complete the request.
5.5.5 Sector Number (LBA 7-0) Register (Address - 1F3h[173h]; Offset 3)
This register contains the starting sector number or bits 7-0 of the Logical Block Address (LBA) for any CompactFlash
Storage Card data access for the subsequent command.
5.5.6 Cylinder Low (LBA 15-8) Register (Address - 1F4h[174h]; Offset 4)
This register contains the low order 8 bits of the starting cylinder address or bits 15-8 of the Logical Block Address.
5.5.7 Cylinder High (LBA 23-16) Register (Address - 1F5h[175h]; Offset 5)
This register contains the high order bits of the starting cylinder address or bits 23-16 of the Logical Block Address.
5.5.8 Drive/Head (LBA 27-24) Register (Address 1F6h[176h]; Offset 6)
The Drive/Head register is used to select the drive and head. It is also used to select LBA addressing instead of
cylinder/head/sector addressing. The bits are defined as follows:
Figure: Drive/Head Register
Bit 7: this bit is specified as 1 for backward compatibility reasons. It is int ended that this bit will become obsolete in a
future revision of the specification. This bit is ignored by some controllers in some commands.
Bit 6: LBA is a flag to select either Cylinder/Head/Sector (CHS) or Logical Block Address Mode (LBA). When LBA=0,
Cylinder/Head/Sector mode is selected. When LBA=1, Logical Block Address is selected. In Logical Block Mode,
the Logical Block Address is interpreted as follows:
LBA7-LBA0: Sector Number Register D7-D0.
LBA15-LBA8: Cylinder Low Register D7-D0.
LBA23-LBA16: Cylinder High Register D7-D0.
LBA27-LBA24: Drive/Head Register bits HS3-HS0.
Bit 5: this bit is specified as 1 for backward compatibility reasons. It is int ended that this bit will become obsolete in a
future revisions of the specification. This bit is ignored by some controllers in some commands.
Bit 4 (DRV): DRV is the drive number. When DRV=0, drive (card) 0 is selected. When DRV=1, drive (card) 1 is selected.
Setting this bit to 1 is obsolete in PCMCIA modes of operation. If the obsolete functionality is support by a CF Storage
Card, the CompactFlash Storage Card is set to be Card 0 or 1 using the copy field (Drive #) of the PCMCIA Socket
& Copy configuration register.
Bit 3 (HS3): when operating in the Cylinder, Head, Sector mode, this is bit 3 of the h ead number.