Specifications

Chapter 3 Hardware
LittleBoard 735 Reference Manual 21
Parallel Port Interface
Parallel port supports standard parallel, Bi-directional, ECP and EPP protocols. The SCH3114I-NU chip
(U15) provides separate parallel port interface signals.
The parallel header uses 26 pins, 2 rows, odd/even sequence (1, 2), with 0.100" pitch.
Note: The shaded areas denote power or ground. The signals marked with * = Negative true logic.
Table 3-4. Parallel Interface Pin Signals (J16)
Pin # Signal In/Out Description
1 Strobe* Out Strobe* – This is an output signal used to strobe data into the printer.
I/O pin in ECP/EPP mode.
2 AFD* Out Auto Feed* – This is a request signal into the printer to automatically
feed one line after each line is printed.
3 PD0 I/O Parallel Port Data 0 – These pins (0 to 7) provide parallel port data.
4 ERR* Out Error* – This is a status output signal from the printer. A Low State
indicates an error condition on the printer.
5 PD1 I/O Parallel Port Data 1 – Refer to pin-3 for more information.
6 INIT* Out Initialize* – This signal used to Initialize printer. Output in standard
Mode, I/O in ECP/EPP mode.
7 PD2 I/O Parallel Port Data 2 – Refer to pin-3 for more information.
8 SLIN Out Select In – This output signal is used to select the printer. I/O pin in
ECP/EPP mode.
9 PD3 I/O Parallel Port Data 3 – Refer to pin-3 for more information.
10,
12
GND Ground
11 PD4 I/O Parallel Port Data 4 – Refer to pin-3 for more information.
13 PD5 I/O Parallel Port Data 5 – Refer to pin-3 for more information.
14,
16
GND Ground
15 PD6 I/O Parallel Port Data 6 – Refer to pin-3 for more information.
17 PD7 I/O Parallel Port Data 7 – Refer to pin-3 for more information.
18,
20
GND Ground
19 ACK* In Acknowledge* – This printer output status indicates it has received
the data and is ready to accept new data if the signal state is Low.
21 BUSY In Busy – This printer output status indicates the printer is not ready to
accept data if the signal state is High.
22,
24
GND Ground
23 PE In Paper End – The printer output status indicates the printer is out of
paper if the signal state is High.
25 SLCT In Select – This printer output status indicates the printer is selected and
powered on if the signal state is High.
26 Key/NC Key - Not connected