READ FPDMA QUEUED (60h) - NCQ(Native Command Queuing)

READ FPDMA QUEUED (60h)

Inputs:

Register		7	6		5	4	3	2	1	0
Features	Current	Sector count (7:0)
	Previous	Sector count (15:8)
Sector Count	Current	TAG						Reserved
	Previous	PRIO(1:0)		Reserved
LBA Low	Current	LBA (7:0)
	Previous	LBA (31:24)
LBA Mid	Current	LBA (15:8)
	Previous	LBA (39:32)
LBA High	Current	LBA (23:16)
	Previous	LBA (47:40)
Device		FUA	1		Res	0	Reserved
Command		60h

TAG: The TAG value shall be assigned by host software to be different from all other TAG values corresponding to outstanding commands. The assigned TAG value shall not exceed the value specified in IDENTIFY DEVICE word 75.

PRIO: The Priority (PRIO) value is assigned by the host based on the priority of the command issued. The device should complete high priority requests in a more timely fashion than normal and isochronous requests. The device  hould complete isochronous requests prior to its associated deadline.

00b Normal Priority

01b Isochronous – deadline dependent priority

10b High priority

11b Reserved

FUA:When set to one forces the data to be retrieved from the storage media regardless of whether the storage device holds the requested information in its buffers or cache. If the device holds a modified copy of the requested data as a result of having cached writes, the modified data is first written to the media before being retrieved from the storage media as part of this operation. When cleared to zero the data may be retrieved either from the device’s storage media or from buffers/cache that the device may include.

Others:All other registers have contents consistent with the READ DMA QUEUED EXT command defined in the ATA8-ACS standard, including the Sector Count 15:0 convention where a value of zero specifies that 65,536 sectors are to be transferred.