When using IORDY, the drives operate at programmed timing specifica-
tions, as shown below.
Time Description Min Max
T0 Cycle time 120 nsec —
T1 Address valid until IOCS16– is asserted — 30 nsec
T2
Drive address (CS1FX–, CS3FX–,
DA0, DA1 and DA2) valid before DIOR–
or DIOW– setup
25 nsec —
T3 IORDY setup time — —
T4
DIOW– or DIOR– pulse width (8-bit) 70 nsec —
DIOW– or DIOR– pulse width (16-bit) 70 nsec —
T5 IORDY pulse width —
1,250
nsec
T6 DIOW– data setup 20 nsec —
T7 DIOR– data setup 20 nsec —
T8 DIOR– data hold 5 nsec —
T9 DIOW– data hold 10 nsec —
T10 DIOW– or DIOR– to address valid hold 5 nsec —
T11 Address valid until IOCS16– is negated — 25 nsec
Address valid
DIOR− or DIOW−
Write data valid
Read data valid
IOCS16−
T1
T0
T2
T4
T6
T7
T9
T8
T11
T10
T3
IORDY
T5
Figure 9. Programmed I/O timing with IORDY
38 Medalist Pro 6450/6451 Product Manual, Rev. B