Seagate 6451, 6450 manual Programmed I/O timing with Iordy

38 Medalist Pro 6450/6451 Product Manual, Rev. B

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

								T8
	T1				T7
		T2		T6			T9
			T3	T5
				T4					T10		T11
				T0
Figure 9. Programmed I/O timing with IORDY
Time	Description						Min				Max
T0	Cycle time					120 nsec					—
T1	Address valid until IOCS16– is asserted						—			30 nsec
T2	Drive address (CS1FX–, CS3FX–,						25 nsec				—
	DA0, DA1 and DA2) valid before DIOR–
	or DIOW– setup
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