Epson 8900 Series manual Parallel Interface Timing Requirements

3.The printer activates ACK- (e) to signal the host that the receive buffer has received the character.

4.If the character does not fill the receive buffer, the printer deactivates BUSY and ACK- (f) to notify the host that the transfer operation is complete. The host can then initiate another data-transfer cycle.

If a character-transfer cycle fills the printer receive buffer, BUSY remains active until the buffer empties to the ready point. The printer then deactivates BUSY to allow the host to initiate another character-transfer cycle.

	Parallel Interface Timing Requirements
Item	Ref.	Timing Requirements
DATA1-8	a	The host writes a character to the
		interface.
	a-b	Data stabilization time, 0.5 μs min.
	b-c	Data hold time, 0.5 μs min.
STROBE-	b	Leading edge must not occur in less than
		0.5 μs after the character has been
		written to the interface. This allows time
		for the data to stabilize.
	b-d	Minimum pulse width, 1.0 μs.
	b-h	Minimum time between pulses, 1.0 μs.
BUSY	b	Leading edge occurs within 100 ns
		after the leading edge of STROBE-.
	f	Trailing edge must occur before the host
		can strobe the next character into the
		receive buffer. For normal write cycles
		(receive buffer not full), this occurs at
		10 μs min., 500 μs nom., and 1000 μs
		max. after the leading edge of STROBE-.
ACK-	e-f	Pulsewidth: 2.0 μs min., 3.0 μs nom.,
		and 6.0 μs max.

Communication Interfaces 10-12