Samsung S3C6400X User Manual page 1115

IRDA
4PPM decoding and CRC decoding is carried out.
MEDIUM-SPEED INFRARED (MIR) MODE (IRDA 1.1)
In MIR mode, data communicates at the speed of 1.152Mbps, and 0.576Mbps (half mode). The payload data is
wrapped around by Start Flags, CRC-16, and Stop Flags. The Start Flag must be at least two bytes. In
transmitting and receiving process, the basic wrapping and de-wrapping processes are same as the FIR mode.
ㄷThe MIR mode needs a bit-stuffing procedure. Bit stuffing in MIR mode have the core insert zero bit per every 5
consecutive ones in transmission mode. In receiving mode, the stuffed bit must be removed. Like the fir mode
case, three different kinds of errors (crc, phy and frame length error) can be reported to the microcontroller in
receiving mode by reading the LSR register.
The diagram below shows the data structure of MIR frame.
STA
STA
CRC16 : CCITT 16 bit CRC
STO
The MIR pulse is modulated by 1/4 pulse format. The below diagram shows the pulse generation.
1.152M
NRZ Data
MIR Pulse
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
38-8
Specifications and information herein are subject to change without notice.
STA Link layer frame (Payload)
: Beginning flag, 01111110 binary
: Ending flag, 01111110 binary
Figure 38-4 Pulse modulation in MIR mode
S3C6400X RISC MICROPROCESSOR
CRC16 STO