LPC47N227TQFP Standard Microsystems (SMSC), LPC47N227TQFP Datasheet - Page 84

• Manufacturer Part Number: LPC47N227TQFP
• Manufacturer: Standard Microsystems (SMSC)

Specifications of LPC47N227TQFP

• Lead Free Status / RoHS Status: Not Compliant

INFRARED INTERFACE
The LPC47N227 infrared interface provides a two-way wireless communications port using infrared as
the transmission medium.
Several infrared protocols have been provided in this implementation
including IrDA v1.2 (SIR/FIR), ASKIR, and Consumer IR (FIGURE 2). For more information consult
the SMSC Infrared Communication Controller (IRCC) specification.
The IrDA v1.0 (SIR) and ASKIR formats are driven by the ACE registers found in UART2. The UART2
registers are described in “Serial Port (UART)” section. The base address for UART2 is programmed
in CR25, the UART2 Base Address Register (see section CR25 subsection in the Configuration
seciton).
The IrDA V1.2 (FIR) and Consumer IR formats are driven by the SCE registers. Descriptions of these
registers can be found in the SMSC Infrared Communications Controller Specification. The Base
Address for the SCE registers is programmed in CR2B, the SCE Base Address Register (see CR28
subsection in the Configuration section).
IrDA SIR/FIR and ASKIR
IrDA SIR (v1.0) specifies asynchronous serial communication at baud rates up to 115.2Kbps. Each
byte is sent serially LSB first beginning with a zero value start bit. A zero is signaled by sending a
single infrared pulse at the beginning of the serial bit time. A one is signaled by the absence of an
infrared pulse during the bit time. Please refer to “Timing Diagrams” section for the parameters of
these pulses and the IrDA waveforms.
IrDA FIR (v1.2) includes IrDA v1.0 SIR and additionally specifies synchronous serial communications at
data rates up to 4Mbps.
Data is transferred LSB first in packets that can be up to 2048 bits in length. IrDA v1.2 includes
.576Mbps and 1.152Mbps data rates using an encoding scheme that is similar to SIR. The 4Mbps data
rate uses a pulse position modulation (PPM) technique.
The ASKIR infrared allows asynchronous serial communication at baud rates up to 19.2Kbps. Each
byte is sent serially LSB first beginning with a zero value start bit. A zero is signaled by sending a
500KHz carrier waveform for the duration of the serial bit time. A one is signaled by the absence of
carrier during the bit time. Refer to “Timing Diagrams” section for the parameters of the ASKIR
waveforms.
Consumer IR
The LPC47N227 Consumer IR interface is a general-purpose Amplitude Shift Keyed encoder/decoder
with programmable carrier and bit-cell rates that can emulate many popular TV Remote encoding
formats; including, 38KHz PPM, PWM and RC-5. The carrier frequency is programmable from 1.6MHz
to 6.25KHz. The bit-cell rate range is 100KHz to 390Hz.
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