Enclosure Service Interface(Esi) Specification; 4.4.1 Discovery Process - Hitachi DK32EJ - Ultrastar Series 36.9 GB Hard Drive Reference Manual

OEM MANUAL:K6602771
4.4

ENCLOSURE SERVICE INTERFACE(ESI) SPECIFICATION

This controller supports the ESI (Enclosure Service Interface) specification
provided in SFF-8045 and SFF-8067.
The host computer can send data to the enclosure using the SEND DIAGNOSTIC
command or receive data from the enclosure using RECEIVE DIAGNOSTIC
RESULTS command.

4.4.1 DISCOVERY PROCESS

An SFF-8067 device requests access to the enclosure's control circuitry by
asserting Parallel ESI signal. The enclosure shall invert SEL_0 – SEL_3 within 1
microsecond. SEL_4 shall take on the value corresponding to –ENCL_ACK,
SEL_5 and SEL_6 shall be released so that this controller can manage them as
–DSK_RD and –DSK_WR respectively, and SEL_0, SEL_1, SEL_2 and SEL_3
shall be replaced by the enclosure with the complement of their values as a
selection ID.
After the –ENCL_ACK is received by this controller, this controller asserts both
-DSK_RD and –DSK_WR together. The enclosure shall negate –ENCL_ACK
within 100 microseconds. If the enclosure does not negate –ENCL_ACK within 100
microseconds, this controller assumes that the enclosure is an SFF-8045 enclosure
that provides parallel ESI information and that by chance the Parallel ESI
information contained the inverted SEL_0 – SEL_3 bits and asserted the –
ENCL_ACK bit at the proper time. This controller posts the information using the
SFF-8045 format.
If the SEL_0 – SEL_3 value is not complemented within 1 microsecond after the
Hitachi FC Disk Drive asserts Parallel ESI, this controller considers that the
enclosure is compliant with SFF-8045.
Discovery Flow Chart is shown in Figure 4-1.
4 SCSI BUS
Revision: 2 / Date: 2002.12.19
Page: 99 / 313