Apple 310 manual Signal

C H A P T E R 1

LaserWriter Select 310 Hardware

Table 1-3Signal descriptions for a Centronics parallel port (continued)

Pin
number	Signal name	I/O	Description
19-30	SIGNAL	–	Signal ground
	GROUND
31	Not connected	–	This line is not connected
32	/FAULT	O	Fault signal; asserted if there is a printer
			problem
33-36	Not connected	–	These lines are not connected

NOTE Inputs and outputs are referenced to the printer. An input (I) signal is sent from the host computer to the printer, and an output (O) signal is sent from the printer to the host.

Figure 1-4Timing for a Centronics interface

Data

a

/PSTROBE

PBUSY

b

d

c

e

f

/PACK

g

Timing specification	Min. value	Typical value	Max. value
a. Data setup time before PSTROBE on	0.5µsec
b. PSTROBE on pulse width	1.0µsec		500µsec
c. Data hold time after PSTROBE off	0.5µsec
d. PSTROBE on to PBUSY on	0.0µsec		1.0µsec
e. Duration of PBUSY on (printer on line)	10.0µsec
f. PBUSY off to /PACK on	0.0µsec	2.5µsec
g. /PACK on pulse width	1.5µsec		10.0µsec

Communication Ports 7