C-4

Appendix C—Parallel Interface

 

 

 

 

 

 

Signal Pin #

 

 

 

 

 

 

 

and Direction

Signal Name

Description

 

1

&

STROBE*

Synchronous input signal for strobing data into the

 

 

 

 

printer. Normally high. Pulse width minimum is 1 ms.

 

2

&

DATA 1

These 8 signals represent the 8-bit data byte.

 

3

&

DATA 2

All eight bits of each character are transmitted to the

 

4

&

DATA 3

printer simultaneously. A high level represents a

 

5

&

DATA 4

binary "1" digit; a low level represents a binary "0"

 

6

&

DATA 5

digit. Data pulse width minimum is 3 ms. Data lines

 

7

&

DATA 6

must be asserted before the strobe goes low.

 

8

&

DATA 7

 

 

9

&

DATA 8

 

 

10

%

ACKNLG*

The printer sends this pulse to the computer after

 

 

 

 

each character is received. ACKNLG* may be

 

 

 

 

referred to as a "data request pulse," indicating that

 

 

 

 

data were received, and the printer is ready to

 

 

 

 

accept more. ACKNLG* is set high until it receives a

 

 

 

 

character, then goes low with a pulse width of 5 ms.

 

 

 

 

This signal works together with the BUSY signal.

 

11

%

BUSY

When high, data transfer from the computer to the

 

 

 

 

printer is prevented. BUSY is set high when a

 

 

 

 

character is strobed into the parallel port, and set

 

 

 

 

low when a byte has been read. This signal works

 

 

 

 

together with the ACKNLG* signal.

 

12

%

PAPER OUT

A high signal indicates the printer is out of paper.

 

 

 

 

The signal comes directly from the printer's paper

 

 

 

 

out switch through a buffer. The buffer also drives

 

 

 

 

the PAPER indicator on the switch panel.

 

 

 

 

 

Parallel Interface Pin Assignments

Page 370
Image 370
Epson 4100 manual Parallel Interface Pin Assignments