Figure 9. Programmed I/O Timing With Iordy - Seagate Medalist Pro Series Product Manual

38 Medalist Pro 6450/5040 Product Manual, February 1997
When using IORDY, the drives operate at programmed timing specifica-
tions, as shown below.
Address valid
IOCS16
DIOR or DIOW
IORDY
Write data valid
Read data valid
T1

Figure 9. Programmed I/O timing with IORDY

Time Description
T0 Cycle time
T1 Address valid until IOCS16– is asserted
Drive address (CS1FX–, CS3FX–,
T2
DA0, DA1 and DA2) valid before DIOR–
or DIOW– setup
T3 IORDY setup time
DIOW– or DIOR– pulse width (8-bit)
T4
DIOW– or DIOR– pulse width (16-bit)
T5 IORDY pulse width
T6 DIOW– data setup
T7 DIOR– data setup
T8 DIOR– data hold
T9 DIOW– data hold
T10 DIOW– or DIOR– to address valid hold
T11 Address valid until IOCS16– is negated
T7
T2 T6
T3 T5
T4
T0
120 nsec
T8
T9
T10 T11
Min Max
—
— 30 nsec
25 nsec —
— —
70 nsec —
70 nsec —
1,250
—
nsec
20 nsec —
20 nsec —
5 nsec —
10 nsec —
5 nsec —
— 25 nsec