Cylinder Low Register, Data Register | Hitachi HCS721075CLA332

8.4Cylinder Low Register

This register contains the low order bits of the starting cylinder address for any disk access. At the end of the command, this register is updated to reflect the current cylinder number.

In LBA Mode this register contains Bits 8-15. At the end of the command, this register is updated to reflect the current LBA Bits 8-15.

The cylinder number may be from zero to the number of cylinders minus one.

When 48-bit addressing commands are used, the "most recently written" content contains LBA Bits 8-15, and the "previous content" contains Bits 32-39.

8.5Data Register

This 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, and configuration information is transferred on an Identify Device command.

All data transfers are 16 bits wide, except for ECC byte transfers, which are 8 bits wide. Data transfers are PIO only.

The register contains valid data only when DRQ=1 in the Status Register.

8.6Device Control Register

Device Control Register

HOB

SRST

-IEN

Table 28 Device Control Register

Bit Definitions

HOB

SRST (RST)

HOB (high order byte) is defined by the 48-bit Address feature set. A write to any Command Register shall clear the HOB bit to zero.

Software Reset. The device is held reset when RST=1. Setting RST=0 reenables the device.

The host must set RST=1 and wait for at least 5 microseconds before setting RST=0, to ensure that the device recognizes the reset.

-IEN	Interrupt Enable. When -IEN=0, and the device is selected, device interrupts to

	the host will be enabled. When -IEN=1, or the device is not selected, device
	interrupts to the host will be disabled.

Hitachi hard disk drive specifications

HCS721016CLA382, HCS721050CLA382, HCS721025CLA382, HDP725050GLA360, HUA722050CLA330/1 specifications

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The HDS721032CLA362 and HDS721032CLA662 share many similarities and are both designed for budget-conscious consumers. With a capacity of 320GB and a 7200 RPM, they offer efficient storage solutions for everyday tasks. The 32MB cache buffer enables efficient caching of frequently accessed files, providing a smooth experience for users.

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