Toshiba 3006GAL, 4006GAH, MK6006GAH 10.12 Reset

360050398

10.12 Reset

A RESET condition sets the drive ( or both drives in case of Drive0/Drive1 connection ) BSY, allowing the drive to perform the specified initialization required for normal operation.

A RESET condition can be generated by both hardware and software. There are two hardware resets, one is by the Host (- RESET) and the other is by the drive power sense circuitry. These resets are set high when the system and the drive respectively acknowledge specified supply voltage ( See 6.1).

The other reset is software generated. The Host can write to the Device Control register and set the reset bit. The host software condition will continue until the reset bit is set to zero.

Once the reset is negated and the drive is re-enabled, with BSY still active, the drive will perform necessary hardware initialization, clear any previously programmed drive parameters and revert to the defaults, load the Task File registers with their initial values, and then clear BSY. No interrupt is generated when initialization is complete. The initial values ( hex ) for the Task File registers are as follows.

Table 10.12-1 Initialization of Task File registers

REGISTER	POWER ON	HARDWARE RESET	SOFTWARE RESET
Data	00	00	00
Error	01	01	01
Sector Count	01	01	01
Sector Number	01	01	01
Cylinder Low	00	00	00
Cylinder High	00	00	00
Device/Head Register	00	00	00
Status/Alternate Status	50 or 52	50 or 52	50 or 52
Device address9	7E or FE	7E or FE	7E or FE
ECC Length	4 bytes	4 bytes	no change(*1)
Data Buffer	undefined	undefined	no change
Addressing mode	default	default	no change
Auto stand-by mode	disable	disable	no change
Read Cache	enable	enable	no change (*1)
Write Cache10	enable	enable	no change (*1)
Multiple mode	16 sectors	16 sectors	no change (*1)
DMA transfer mode	Multiword	Multiword DMA mode	no change(*1)
	DMA mode 2	2
PIO transfer mode	PIO mode 4	PIO mode 4 flow	no change(*1)
	flow control	control

(*1): Software reset settings are affected by set feature command.

9ATA-2 Notes: This register is obsolete. It is recommended that a device not respond to a read of this address. If a device does respond, it shall be sure not to drive the DD7 signal to prevent possible conflict with floppy disk implementations.

The drive supports this register to maintain compatibility for ATA-1.

10ATA-2 Notes: The default mode for write cache is “disable” after ATA-2. This is violation of ATA-2 specification. This setting can be changed by factory.

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