Samsung M9T manual Command Block Register Descriptions

6.3.3.2Device Control Register (ex. 3F6h)

The bits in this register are as follows:

7	6	5	4	3	2	1	0
HOB	R	R	R	R	SRST	nIEN	0

•HOB is the High Order Byte used for host to access the Extended Registers in the 48-bit LBA mode

•SRST is the host software reset bit. The drive is held reset when this bit is set. If two disk drives are daisy chained on the interface, this bit resets both simultaneously.

•nIEN is the enable bit for the drive interrupt to the host. When nIEN=0, and the drive is selected, INTRQ is enabled through a tri-state buffer. When nIEN=1, or the drive is not selected, the INTRQ signal is in a high impedance state.

•R is for reserved

6.3.4Command Block Register Descriptions

6.3.4.1Data Register (Ex. 1F0h)

This 16-bit register is used to transfer data blocks between the device data buffer and the host. It is also the register through which sector information is transferred on a Format Track command. Data transfers may be either PIO or DMA.

6.3.4.2Features Register and Feature Extended Register (Ex. 1F1h)

This register is command specific and used to enable and disable features of the interface (e.g., by the Set Features command to enable and disable caching). The Feature Extended Register contains the upper byte of the Feature Register.

6.3.4.3Sector Number Register and Sector Number Extended Register (Ex. 1F3h)

In CHS mode this register contains the starting sector number for any disk data access for the subsequent command. The sector number is from 1 to the maximum number of sectors per track. In LBA mode this register contains bits 0-7 of the LBA. The Sector Number Extended Register is for bits 25-31 of the 48-bit LBA. See the command descriptions for the contents of the register at command completion (whether successful or unsuccessful).

6.3.4.4Error Register (Ex. 1F1h)

This register contains status from the last command executed by the drive or a Diagnostic Code.

At the completion of any command except Execute Drive Diagnostic, the contents of this register are valid when ERR=1 in the Status register.

Following a power-on, a reset, or completion of an Execute Drive Diagnostic command, this register contains a Diagnostic Code.

	7	6	5	4	3	2	1	0
	#	#	#	#	#	ABRT	#	#
Spinpoint M9T Product Manual REV 1.0								38