User guide

900S Series Industrial Grade CFast Product Manual v2.0Cactus Technologies

4.1.4. Sector Count Register

This register contains the number of sectors of data requested to be transferred on a read or write

operation between the host and the SSD. If the value in this register is zero, a count of 256 sectors

is specied. If the command was successful, this register is zero at command completion. If not

successfully completed, the register contains the number of sectors that need to be transferred in

order to complete the request.

4.1.5. Sector Number (LBA 7-0) Register

This register contains the starting sector number or bits 7-0 of the Logical Block Address (LBA) for

any FlashDrive data access for the subsequent command.

4.1.6. Cylinder Low (LBA 15-8) Register

This register contains the low order 8 bits of the starting cylinder address or bits 15-8 of the Logical

Block Address.

4.1.7. Cylinder High (LBA 23-16) Register

This register contains the high order bits of the starting cylinder address or bits 23-16 of the Logical

Block Address.

4.1.8. Drive/Head (LBA 27-24) Register

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 dened as follows:

D7 D6 D5 D4 D3 D2 D1 D0

1 LBA 1 DRV HS3 HS2 HS1 HS0

Bit 7 This bit is set to 1.

Bit 6 LBA is a ag 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:

LBA07-LBA00: Sector Number Register D7-D0.

LBA15-LBA08: 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 set to 1.

Bit 4 (DRV) This bit will have the following meaning. DRV is the drive number. When DRV=0,

drive 0 is selected When DRV=1, drive 1 is selected.

Bit 3 (HS3) When operating in the Cylinder, Head, Sector mode, this is bit 3 of the head

number. It is Bit 27 in the Logical Block Address mode.

Bit 2 (HS2) When operating in the Cylinder, Head, Sector mode, this is bit 2 of the head

number. It is Bit 26 in the Logical Block Address mode.

Bit 1 (HS1) When operating in the Cylinder, Head, Sector mode, this is bit 1 of the head

number. It is Bit 25 in the Logical Block Address mode.

Bit 0 (HS0) When operating in the Cylinder, Head, Sector mode, this is bit 0 of the head

number. It is Bit 24 in the Logical Block Address mode.