EPSON Stylus COLOR 500

The following table lists the parallel connector pin assignments and describes their respective interface signals.

Pin

 

 

 

 

no.

Signal name

GND

In/Out

Description

 

 

 

 

 

1

HostClk

19

In

Strobe pulse. Input data is latched

 

 

 

 

at falling edge of the signal.

 

 

 

 

 

2

DATA 1

20

In

Bit 0: LSB Parallel input data to the

 

 

 

 

printer.

 

 

 

 

 

3

DATA 2

21

In

These signals represent information

 

 

 

 

in bits 0 to 7 of parallel data

4

DATA 3

22

In

respectively. Each signal is at HIGH

 

 

 

 

5

DATA 4

23

In

level when data is logical 1 and LOW

when it is logical 0. These signals

 

 

 

 

6

DATA 5

24

In

are used to transfer the 1284

 

 

 

 

extensibility request values to the

7

DATA 6

25

In

printer.

 

 

 

 

8

DATA 7

26

In

 

 

 

 

 

 

9

DATA 8

27

In

 

 

 

 

 

 

10

PtrClk

28

Out

Used to qualify data being sent to

 

 

 

 

the host. Set LOW then HIGH to

 

 

 

 

cause an interrupt indicating to host

 

 

 

 

that data is available.

 

 

 

 

 

11

PtrBusy/

29

Out

Data bits 3 then 7 indicate forward

 

DataBit-3,7

 

 

channel busy status.

 

 

 

 

 

12

ACkDataReq/

28

Out

Data bits 2 then 6. Set HIGH until

 

DataBit-2,6

 

 

host requests data transfer, then

 

 

 

 

follows nData Avail (nFault).

 

 

 

 

 

13

Xflag/

28

Out

X-flag signal and reverse channel

 

DataBit-1,5

 

 

transfer data bit 1 then 5.

 

 

 

 

 

14

HostBusy

30

In

Set LOW to indicate that host can

 

 

 

 

receive peripheral device to host

 

 

 

 

data. Then set high to acknowledge

 

 

 

 

receipt of that nibble. Set high in

 

 

 

 

response to PtrClk (nAck) low pulse

 

 

 

 

to re-enter reverse data transfer

 

 

 

 

phase.

 

 

 

 

 

31

INIT

30

In

Not used

 

 

 

 

 

32

DataAvail./

29

Out

This signal is LOW when the printer

 

DataBit-0,4

 

 

is in an error state

 

 

 

 

 

36

1284-Active

30

In

1284 active signal

 

 

 

 

 

18

Logic H

-

Out

Pulled up to +5V through 3.9 kΩ

 

 

 

 

resistance.

 

 

 

 

 

35

+5V

-

Out

Pulled up to +5V through 3.3 kΩ

 

 

 

 

resistance.

 

 

 

 

 

17

Chassis

-

-

Chassis GND

 

 

 

 

 

16,33,

GND

-

-

Signal GND

19–30

 

 

 

 

 

 

 

 

 

15, 34

NC

-

-

Not connected

 

 

 

 

 

Note:

The column heading “In/Out” refers to the direction of the signal flow as viewed from the printer.

Timing chart

The figure below shows the timing chart for the parallel interface.

BUSY

ACKNLG

DATA

STROBE

0 μs (Min.)

0.5 μs (Min.)

5 μs (Typ.)

0 μs (Min.)

 

Transition time (both the rise and the fall) of every signal must be less than 0.2 μs.

Serial Interface

The printer’s built-in serial interface is based on the RS-422 standard so you can connect the printer to an Apple Macintosh.

Standard:

Based on RS-422

Synchronization:

Asynchronous

Bit rate:

57.6 Kbps/230.4 Kbps

Handshaking:

DTR protocol

Word format:

 

Data bit

8 bits

Parity bit

None

Start bit

1 bit

Stop bit

1 bit

Connector:

8-pin mini-circular connector

Recommended

 

cable:

Apple System Peripheral-8 cable (M0197)

Initialization

The printer can be initialized (returned to a fixed set of conditions) in these ways:

Hardware

• The printer is turned on.

initialization

• The printer receives an

INIT

signal

 

from the parallel interface: pin 31 goes LOW

 

 

Software

• Software sends the ESC @ (initialize the printer)

initialization

command; the last panel settings are kept

 

 

 

 

Each initialization method resets the font according to the default settings selected using the control panel. However, ESC @ does not initialize the printer mechanism, clear the input data buffer, or clear the user-defined character set.

Ink Jet Printers

6/96

EPSON Stylus COLOR 500 - 5