Figure 9. Programmed I/O Timing With Iordy; Nsec - Seagate Medalist 1640 Product Manual

36 Medalist 1640 and 2140 Product Manual, January 1996
When using IORDY, the drive operates at programmed timing specifica-
tions, as shown below.

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
Address invalid until IOCS16-- is
T11
negated
Min Max

120 nsec

----
---- 20 nsec
25 nsec ----
---- 25 nsec
70 nsec ----
70 nsec ----
1,250
----
nsec
20 nsec ----
20 nsec ----
5 nsec ----
10 nsec ----
5 nsec ----
---- 5 nsec