TechNote IP-SPEC-02
Intelliprint Series
Parallel Port Specifications
7 Apr 1999 Ed Palmer
SUMMARY: This document provides technical details on the operation of the parallel port integrated into the Intelliprint controller.
PINOUT AND SIGNALS
The connector used is a standard 36 pin female connector similar to AMP 555520. The outer connector shield is connected to chassis ground.
|
1 |
STROBE- Active Low, from host, indicates valid data |
19 |
CHASSIS GND |
|
2 |
DATA1 |
20 |
SIGNAL GND |
|
3 |
DATA2 |
21 |
SIGNAL GND |
|
4 |
DATA3 |
22 |
SIGNAL GND |
|
5 |
DATA4 |
23 |
SIGNAL GND |
|
6 |
DATA5 |
24 |
SIGNAL GND |
|
7 |
DATA6 |
25 |
SIGNAL GND |
|
8 |
DATA7 |
26 |
SIGNAL GND |
|
9 |
DATA8 |
27 |
SIGNAL GND |
|
10 |
ACK- Active Low, from printer, acknowledges data in standard mode, 700-nsec minimum. |
28 |
SIGNAL GND |
|
11 |
BUSY Active High, from printer, asserted whenever the printer can not receive data. |
29 |
SIGNAL GND |
|
12 |
PAPER EMPTY Active Low, from printer, asserted when the selected paper tray is empty and tray linking is not enabled. |
30 |
SIGNAL GND |
|
13 |
SELECT Active High, from printer, asserted when the printer is ready and selected. The deselected state causes the BUSY and FAULT signals to assert. |
31 |
INIT- Active Low, from the host, used to reset the printer and clear it’s buffers. |
|
14 |
HBUSY Active High, from the host, used in 1284 negotiation. |
32 |
FAULT- Active Low, from the printer, used to indicate a fault condition in the printer. |
|
15 |
(N/C) |
33 |
(N/C) |
|
16 |
SIGNAL GND |
34 |
(N/C) |
|
17 |
(N/C) |
35 |
(N/C) |
|
18 |
+5 Volts DC 1 Amp Max |
36 |
A1284 Active High, from the host, informs the printer to enter one of the 1284 modes. |
ELECTRICAL SPECIFICATIONS
The printer uses an industry standard driver and receiver combination IC (74VHC161284) that has been specifically designed to conform to the IEEE 1284 specifications. The reader may refer to the IC specification sheet for specs that go beyond the scope of this document. A few of the most common values will be presented here. All output and bi-directional signals have been passed though a series ferrite bead for noise reduction. All signal lines have been coupled to signal ground through a 220pf capacitor for noise immunity.
| Minimum high level input voltage for logic 1 | VIH | 2.0 volts |
| Maximum high level input voltage for logic 0 | VIL | 0.8 volts |
| Minimum high level output voltage for logic 1 | VOH | 3.73 volts |
| Maximum low level output voltage for logic 0 | VOL | 0.77 volts |
| Minimum pull-up resistance | RP | 1.15 K ohms |
| Maximum input current in high state | IIH | 100 microamps |
| Maximum input current in low state | IIL | -5.0 milliamps |
| Maximum output disable current (high) | IOZH | 100 microamps |
| Maximum output disable current (low) | IOZL | -5.0 milliamps |
SIGNAL TIMING
The timing of the main control signals depends on the mode of the parallel port. The printer supports all modes except one in the IEEE 1284 specification. EPP mode is not supported as it is usually only needed for reverse channel devices like scanners or ZIP drives that return large amounts of data back to the host. Reverse channel data is supported on this printer with both Nibble Mode and Byte Mode. The timings of these two modes will not be discussed here as they are in almost complete control of the host. What may be of interest to the user or technician would be Standard Mode and ECP mode. ECP mode with it’s interlocked STROBE and BUSY is a faster interface. A short description of these follows:
Standard Mode
- Host places data on the DATA pins.
- Host asserts STROBE-
- After minimum setup and filtering, printer asserts BUSY and reads the DATA
- Host releases STROBE-
- printer asserts ACK-
- printer releases BUSY
- printer releases ACK
ECP Mode
(Host has negotiated into 1284 mode and the 1284 signal is True)
- Host places data on the DATA pins
- Host asserts STROBE-
- After minimum setup and filtering, printer asserts BUSY and reads the DATA
- Host releases STROBE-
- printer releases BUSY
Following are timing waveforms of Standard Mode and ECP Mode in action. Relative timings can be seen with the three cursors; Trigger, X and O.
Standard Mode Timing
ECP Mode Timing
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Copyright © 2002 GENICOM, Specifications subject to change without notice. ® All trademarks are property of their respective holders at the time of this publication.  If you have any questions or comments regarding this document, please contact TallyGenicom Technical Support. TallyGenicom has taken care to ensure that the information is complete, accurate and up-to-date. However, GENICOM assumes no responsibility for errors or omissions which may occur. All the information provided is subject to change from time to time at the sole discretion of GENICOM. This information is provided "as is" without warranty of any kind. GENICOM disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall GENICOM, or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if GENICOM, or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. |