Samsung 3.5" hard disk drives manual Programming Requirements, Reset Response, Error Posting

DISK DRIVE OPERATION

6.5Programming Requirements

6.5.1 Reset Response

A reset is accepted within 400 nsec after the negation of RESET- or within 400 nsec after SRST has been set in the Device Control register.

When the drive is reset by RESET-, Drive 1 indicates it is present by asserting DASP- within 400 msec, and DASP- remains asserted for 30 seconds or until Drive 1 accepts the first command.

When the drive is reset by SRST, the drive sets BSY=1. See also Device Control register (section 6.3.3.3).

When a reset is accepted, and with BSY set:

a)Both drives perform hardware initialization

b)Both drives clear any previously programmed drive parameters

c)Both drives may revert to the default condition

d)Both drives load the Command Block registers with their default values

e)If it was a hardware reset, Drive 0 waits for DASP- to be asserted by Drive 1

f)If operational, Drive 1 asserts DASP-

g)Drive 0 waits for PDIAG- to be asserted, if Drive 1 asserts DASP-

h)If operational, Drive 1 clears BSY

i)If operational, Drive 1 asserts PDIAG-

j)Drive 0 clears BSY

No interrupt is generated when initialization is complete.

The default values for the Command Block registers, if no self-tests are performed or if no errors occurred, are:

Error	=	01h	Cylinder Low	=	00h
Sector Count	=	01h	Cylinder High	=	00h
Sector Number	=	01h	Drive/Head	=	00h

The Error register contains a Diagnostic Code (see Table 6-3).

Following any reset, the host should issue an Initialize Drive Parameters command to ensure the drive is initialized as desired.

6.5.2 Error Posting

The errors that are valid for each command are defined in Table 6-13.

See sections 6.3.4.4 and 6.3.4.10 for the definition of the Error register and Status register bits.

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