Specifications

Chapter 3 Hardware
LittleBoard 800 Reference Manual 21
Note: The shaded area denotes power or ground. The signals marked with * = Negative true logic.
Serial Interfaces
Two LPC47B272 chips provide the circuitry for the 4 serial ports. One chip provides serial ports 1 and 2
through connector J11 and the second chip provides serial ports 3 and 4 through connector J12. The four
serial ports support the following features:
• Four individual 16550-compatible UARTs
• Programmable word length, stop bits and parity
• 16-bit programmable baud rate generator
• Interrupt generator
• Loop-back mode
• Four individual 16-bit FIFOs
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
Table 3-4. Parallel Interface Pin/Signal Descriptions (J16) (Continued)