Using a printer port to drive the RPC |
| Date: 22 - January 1998 |
Graham Sharples |
| Date: 27 May 1998 (updated) |
Sabananthan Paramananthan |
METHOD 1 , BI-DIRECTIONAL PORT (PS/2)
Port requirement - 8 bit bi-directional (PS/2 or ECP set to PS/2 Mode / Byte Mode) Connections - RPC 25 WAY 'D' printer
| RPC pins |
|
PC (Printer Port) pins |
| Pin Labels |
Pin |
|
PS/2 Pins |
Pin Label |
| GND |
1 |
|
18 to 25 |
Ground |
| D0 |
2 |
 |
2 |
Data 0 |
| D1 |
3 |
|
3 |
Data 1 |
| D2 |
4 |
|
4 |
Data 2 |
| D3 |
5 |
|
5 |
Data 3 |
| TXR |
6 |
 |
1 |
-Strobe |
| TXA |
7 |
 |
12 |
+Paper Out |
| RXR |
8 |
|
13 |
+Printer Selected |
| RXA |
9 |
|
14 |
-Auto Linefeed |
| RES |
10 |
|
16 |
-Initialise Printer |
| 5 Volt |
11 |
|
+5 Volt Supply |
|
| GND |
12 |
|
0 Volt Supply |
|
| +ve interupt |
|
10 |
-Acknowledge |
PC printer port registers (addresses given for base address of 0378)
| 0378 |
data reg |
b7 |
b6 |
b5 |
b4 |
b3 |
b2 |
b1 |
b0 |
| |
|
- |
- |
- |
- |
D3 |
D2 |
D1 |
D0 |
| 0379 |
status reg |
b7 |
b6 |
b5 |
b4 |
b3 |
b2 |
b1 |
b0 |
| |
|
- |
int |
TXA |
RXR |
- |
- |
- |
- |
| 037A |
control reg |
b7 |
b6 |
b5 |
b4 |
b3 |
b2 |
b1 |
b0 |
| |
|
- |
- |
dir |
Ien |
- |
RES |
RXA |
TXR |
For Extended Capabilities Port (ECP) only
| 077A |
Extended Control Register (ECR) |
b7 |
b6 |
b5 |
b4 |
b3 |
b2 |
b1 |
b0 |
| |
|
0 |
0 |
1 |
- |
- |
- |
- |
- |
Printer Port can be configured to operate in ECP mode by changing the Printer Port setting in BIOS from SPP or EPP to ECP. Press DEL key for AWARD BIOS or F1 for AMI BIOS when booting the computer. Then go to Integrated Peripherals section to change the settings for Parallel Port.
However, it may be necessary to change it back to SPP or EPP mode for some printers to operate properly.
int - +ve transition interupt bit, see "interupt drive" Ien - bit is internal interupt enable, not used if polling used
1 = interupt enable , 0 = disabled (polled operation)
dir - bit is internal, controls direction of data output / input
0 = data pins are O/P's, ie drive data to RPC 1 = data pins are I/P's, ie read data from RPC
note - RXA and TXR pins are inverted drives from the register
ie a 1 in the control register gives a 0 on the pin all other registers / bits are true.
METHOD 2 , STANDARD PRINTER PORT (SPP)
| Port requirement |
Standard Printer Port (SPP) |
|
with Open Collector / Pull-up Control lines |
Connections - RPC 25 WAY 'D' printer
| RPC pins |
|
PC (Printer Port) pins |
| Pin Label |
Pin |
|
Pin |
Pin Label |
| GND |
1 |
|
18 to 25 |
Ground |
| D0 |
2 |
|
1 |
-Strobe |
| D1 |
3 |
|
14 |
-Auto Linefeed |
| D2 |
4 |
|
16 |
-Initialise Printer |
| D3 |
5 |
|
17 |
-Select Printer |
| TXR |
6 |
|
2 |
Data 0 |
| TXA |
7 |
|
12 |
Paper Out |
| RXR |
8 |
|
13 |
Printer Selected |
| RXA |
9 |
|
3 |
Data 1 |
| RES |
10 |
|
4 |
Data 2 |
| 5 volt |
11 |
|
+5 Volt supply |
|
| GND |
12 |
|
0 Volt supply |
|
| +ve interupt |
|
|
10 |
-Acknowledge |
PC printer port registers (addresses given for base address of 0378)
| 0378 |
data reg |
b7 |
b6 |
b5 |
b4 |
b3 |
b2 |
b1 |
b0 |
| |
|
- |
- |
- |
- |
- |
RES |
RXA |
TXR |
| 0379 |
status reg |
b7 |
b6 |
b5 |
b4 |
b3 |
b2 |
b1 |
b0 |
| |
|
- |
Int |
TXA |
RXR |
- |
- |
- |
- |
| 037A |
control reg |
b7 |
b6 |
b5 |
b4 |
b3 |
b2 |
b1 |
b0 |
| |
|
- |
- |
dir |
Ien |
D3 |
D2 |
D1 |
D0 |
(B'00000100'= QUIECENT I/P) ( ie. 1111 on data lines )
int - +ve transition interupt bit, see "interupt drive" Ien - bit is internal interupt enable, not used if polling used
1 = interupt enable , 0 = disabled (polled operation)
note - D0, D1 and D3 pins are inverted drives from the register
ie a 1 in the control register gives a 0 on the pin all other registers / bits are true. RPC Dev Kit comes with a DB25 Plug (Male Connector) for Standard Parallell Port with Open Collector / pull -up control lines. To use the RPC Dev Kit in PS/2 Mode, a special pair of interface cables are also provided.
Internet sources of further information Interfacing the IBM PC Parallel Printer Port. Overview
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