30
6. Write I/F Signal Flow (Drive << Host)
Above figure is timing flow presented data transfer from Host to Drive.
And, the followings are those conditions;
1. When the Host write the ATAPI packet command-word
2. When the Host write the Data (ex, Mode select command) - word
3. When the Host write the task file registers - byte
Now, the corresponding register is chosen by control signal HCSO, HCSI, HA [2:0] and the Host write the
command (or Data) through the corresponding register.
To write some words (or bytes), the IOW (IO write signal) must be active - low, that is, the actual Data (HD
[15:0]) will be loaded by the synchronized IOW signal (active-low).
*IOCS16 : depends on the quantity of Data (word or byte), that is, if word, that signal was enabled.
*IORDY : depends on the transfer rate of Host.
Dn-3
Dn-2
Dn-1
Dn
D0
D1
≈
≈
≈
≈
≈
≈
7. Read I/F Signal Flow (Drive >> Host)
Above figure is timing flow presented data transfer from Drive to Host.
And, the followings are those conditions;
1. When the Host read the data from Drive (ex, Read command) - word
2. When the Host read the task file registers - byte
Above timing sequence is similar with the previous write timing sequence.
Only different thing is that the IOW is substituted by IOR (IO read signal)
that is, the actual data will be loaded by the synchronized IOR signal (active -low).
Dn-3
Dn-2
Dn-1
Dn
D0
D1
HA [2:0
]
HCS0, HCS1
IOR
HD [15:0]
IOCS16
IORDY
≈
≈
≈
≈
≈
≈
