Ampro Corporation LITTLE BOARD P5X - Manual (Page 41)

Little Board/P5x Technical Manual
2–23
Infrared (IrDA) Interface
The Little Board/P5x infrared interface provides for a two-way wireless communications port using
infrared as a transmission medium. The Little Board/P5x IrDA interface supports both SIR (Serial
Infrared) and FIR (Fast Infrared) standards . The SIR standard allows serial communication at
baud rates up to 115K Baud. The FIR standard allows data rates up to 4 Mbits/second.
Requirements for an IrDA interface
On the Little Board/P5x, the IrDA physical link hardware consists of an IR transmit encoder and IR
receiver decoder. To implement an IrDA port, the OEM must supply an IR transducer, which
consists of the output driver and IR emitter for transmitting, and the receiver IR detector.
Particular IR transducers may require additional external components.
The IrDA port uses the second serial port to drive its internal encoder/decoder. When using the
IrDA interface, you cannot use serial 2 as an RS-232 port.
IrDA Connector (Part of J24)
The IrDA port pinout is listed in Table 2– 19.
Table 2– 19. IrDA Interface Pinout
J24 Pin
Signal
Name Function
4 IRMODE /
IRRXB
Fast IR Receive/Mode Output:
5 IRTX IR Transmit
6 IRRXA IR Receive (SIR)
There are two popular implementations of Fast IR. One uses a separate receive line capable of
receiving at the higher data rate (up to 4 Mbytes/second). The other is implemented with a mode
control line. When the IR port is set for high speed, the mode output line (FIR/M, J24-4) is high.
This switches the external transceiver to high speed mode.
Multi-Mode Parallel Port
The Little Board/P5x incorporates a multi-mode parallel port. This port supports four modes of
operation:
! Standard PC/AT printer port (output only)
! PS/2-compatible bi-directional parallel port (SPP)
! Enhanced Parallel Port (EPP)
! Extended Capabilities Port (ECP)