Hitachi HDS723020BLA642 manual Read Sectors 20h/21h, Read Sectors Command 20h/21h

7K200 SATA OEM Specification

14.21Read Sector(s) (20h/21h)

Command Block Output Registers																								Command Block Input Registers
Register						7		6			5			4			3		2			1	0	Register						7	6				5		4		3	2	1		0
Data					-		-			-				-		-		-			-		-	Data						-	-			-		-		-		-	-		-
Feature					-		-			-				-		-		-			-		-	Error								...See Below...
Sector Count						V		V			V		V				V		V			V	V	Sector Count						V	V				V		V		V	V	V	V
LBA Low						V		V			V		V				V		V			V	V	LBA Low						V	V				V		V		V	V	V	V
LBA Mid						V		V			V		V				V		V			V	V	LBA Mid						V	V				V		V		V	V	V	V
LBA High						V		V			V		V				V		V			V	V	LBA High						V	V				V		V		V	V	V	V
Device						-		L			-			-			H		H			H	H	Device						-	-				-		-		H	H	H		H
Command					0		0			1		0				0		0			0		R	Status									...See Below...
			Error Register																								Status Register
7	6	5	4	3					2						1					0				7	6	5		4	3			2						1			0
CRC	UNC	0	IDN	0					ABT						T0N							AM		BSY	RDY	DF		DSC	DRQ			COR							IDX		ERR
																						N
0	V	0	V	0							V				0					0				0	V	0		V	-			0						0			V

Table 87 Read Sector(s) Command (20h/21h)

The Read Sector(s) command reads one or more sectors of data from disk media, then transfers the data from the device to the host.

The sectors are transferred through the Data Register 16 bits at a time.

If an uncorrectable error occurs, the read will be terminated at the failing sector.

Output Parameters To The Device

Sector Count	The number of continuous sectors to be transferred. If zero is specified, then 256 sectors
	will be transferred.
LBA Low	The sector number of the first sector to be transferred. (L=0)
	In LBA mode, this register contains LBA bits 0 - 7. (L=1)
LBA High/Mid	The cylinder number of the first sector to be transferred. (L=0)
	In LBA mode, this register contains LBA bits 8 - 15 (Mid), 16 - 23 (High). (L=1)
H	The head number of the first sector to be transferred. (L=0)
	In LBA mode, this register contains LBA bits 24 - 27. (L=1)
R	The retry bit, but this bit is ignored.
Input Parameters From The Device
Sector Count	The number of requested sectors not transferred. This will be zero, unless an
	unrecoverable error occurs.
LBA Low	The sector number of the last transferred sector. (L=0)
	In LBA mode, this register contains current LBA bits 0 - 7. (L=1)
LBA High/Mid	The cylinder number of the last transferred sector. (L=0)
	In LBA mode, this register contains current LBA bits 8 - 15 (Mid), 16 - 23 (High).
	(L=1)
H	The head number of the last transferred sector. (L=0)
	In LBA mode, this register contains current LBA bits 24 - 27. （L=1）

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