DISK DRIVE OPERATION
SpinPoint V40 Product Manual 91
Table 6-16 Register transfer to/from device
PIO timing parameters Mode 0
ns Mode 1
ns Mode 2
ns Mode 3
ns Mode 4
ns Note
t0 Cycle time (min) 600 383 330 180 120 1,4
t1 Address valid to DIOR-/DIOW- setup (min) 70 50 30 30 25
t2 DIOR-/DIOW- pulse width 8-bit (min) 290 290 290 80 70 1
t2i DIOR-/DIOW- recovery time (min) - - - 70 25 1
t3 DIOW- data setup (min) 60 45 30 30 20
t4 DIOW- data hold (min) 30 20 15 10 10
t5 DIOR- data setup (min) 50 35 20 20 20
t6 DIOR- data hold (min) 5 5 5 5 5
T6Z DIOR- data tristate (max) 30 30 30 30 30 2
t9 DIOR-/DIOW- to address valid hold (min) 20 15 10 10 10
tRD Read Data Valid to IORDY active
(if IORDY initially low after tA) (min) 0 0 0 0 0
tA IORDY Setup time 35 35 35 35 35 3
tB IORDY Pulse Width (max) 1250 1250 1250 1250 1250
tC IORDY assertion to release (max) 5 5 5 5 5
NOTES −
1 t0 is the minimum total cycle time, t2 is the minimum command active time, and t2i is the minimum command rec overy
time or command inactive time. The actual cycle time equals the sum of the actual command active time and the actual
command inactive time. The three timing requirements of t0, t2, and t2i shall be met. The minimum total cycle time
requirements are greater than the sum of t2 and t2i. This means a host implementation may lengthen either or both t2 or
t2i to ensure that t0 is equal to or greater than the value reported in the devices IDENTIFY DEVICE data. A device
implementation shall support any legal host implementation.
2 This parameter specifies the time from the negation edge of DIOR- to the time that the data bus is no longer driven by
the device (tri-state).
3The delay from the activation of DIOR- or DIOW- until the state of IORDY is first sampled. If IORDY is inactive
then the host shall wait until IORDY is active before the PIO cycle is completed. If the device is not driving IORDY
negated at the tA after the activation of DIOR- or DIOW-, then t5 shall be met and tRD is not applicable. If the device is
driving IORDY negated at the time tA after the activation of DIOR- or DIOW-, then tRD shall be met and t5 is not
applicable.
4 Mode shall be selected no faster than the highest mode supported by the slowest device.
Figure 6-2 defines the relationships between the interface signals for PIO data transfers. Peripherals
reporting support for PIO mode 3 or 4 shall power up in a PIO mode 0, 1, or 2.
For PIO modes 3 and above, the minimum value of t0 is specified by word 68 in the IDENTIFY DEVICE
parameter list. Table 6-17 defines the minimum value that shall be placed in word 68.
IORDY shall be supported when PIO modes 3 or 4 are the current mode of operation.
NOTE − Some devices implementing the PACKET Command feature set prior to this
standard power up in PIO mode 3 and enable IORDY as the default.