Samsung S5PC100 User Manual page 685

IRDA
4.2 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 should be at least 2 bytes. To transmit
and receive, the basic wrapping and de-wrapping processes are same as FIR mode, but, the MIR mode needs
the 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 should be removed. Three different kinds of errors (CRC,
PHY and frame length error) is reported to the microcontroller in receiving mode by reading the LSR register.
The diagram below shows the data structure of MIR frame.
STA
STA : Beginning flag, 01111110 binary
CRC16 : CCITT 16-bit CRC
STO : Ending flag, 01111110 binary
The MIR pulse is modulated by 1/4 pulse format. The below diagram shows generation of pulse.
1.152M
NRZ Data
MIR Pulse
8.4-6
STA Link layer frame (Payload)
Figure 8.4-4 Pulse Modulation in MIR Mode
S5PC100 USER'S MANUAL (REV1.0)
CRC16 STO