"IDE - hardware reference & information document" - читать интересную книгу автора (Ivopol A.)

passed diagnostics. Following a power-on reset or software
reset, Drive 1 will negate -PDIAG within 1 msec to indicate to
Drive 0 that it is busy.

Drive 1 will then assert -PDIAG within 30 secs to indicate that
it is no longer busy and can provide status information. After
the assertion of -PDIAG, Drive 1 may be unable to accept
commands until it has finished its reset procedure and DRDY is
set.

Following the receipt of a valid Execute Drive Diagnostics
command, Drive 1 will negate -PDIAG within 1 msec to indicate
to Drive 0 that it is busy and has not yet passed its drive
diagnostics. If Drive 1 is pressent, then Drive 0 will wait for
up to 5 msec from the receipt of a valid Execte Drive
Diagnostics command for Drive 1 to assert -PDIAG. Drive 1
should clear BUSY beforeasserting -PDIAG as -PDIAG is used to
indicate the Drive 1 has passed its diagnostics and is ready to
post status.

If -DASP was not asserted by Drive 1 during reset
initialization, Drive 0 will post its own status immediately
after it completes its diagnostics and clear the Drive 1 Status
Register to 00h. Drive 0 may be unable to accept commands until
it has finished its reset procedure and DRDY is set.

-CS1FX
is a chip select generated by address decoding circuitry from
host address lines A3...A9. Usually asserted during I/O
operations to ports 1F0 through 1F7. -CS1FX is used to access
the eight hard disk Command Block Registers.

-CS3FX
is a chip select generated by address decoding circuitry from
host address lines A3...A9. Usually asserted during I/O
operations to ports 3F0 through 3F7. -CS3FX is valid during 8
bit transfers to/from the Control Block Registers, Alternate
Status Register, Device Control Register and drive address.

NOTE: The primary host adapter is accessed via I/O addresses
1FX and 3FX while the secondary host adapter is accessed via
I/O addresses 17X and 37X. See Ed's note under the paragraph
"Register Address Decoding" above.

-DASP
is a time multiplexed signal which indicates that a drive is
active or that Drive 1 is present. It is an open collector
output.

During power-on initialization or after reset, -DASP will be