STIR4200 SigmaTel, STIR4200 Datasheet - Page 10

• Manufacturer Part Number: STIR4200
• Description: USB / IrDA Bridge Controller
• Manufacturer: SigmaTel

STIr4200
USB/IrDA Bridge Controller
5. IR FRAMING FORMATS
10
5.1.
Transmit Frame Format
5.1.1.
SIR Transmit Frame
The SIR rates include 2.4, 9.6, 19.2, 38.4, 57.6, and 115.2 Kbps. For SIR, the frame
presented to the USB bulk transmit interface must be organized in the following
fashion as shown in Figure 4.
Number of following bytes
Figure 4. SIR Transmit Frame Format
MSB CRC
LSB CRC
MSB size
LSB size
0xAA
0xC0
0xC0
0xC0
0xC0
0xC0
0xC1
0x55
Data
Data
Data
Data
Data
Data
Data
…
…
Header ID
BOF = Beginning of frame characters
The number of beginning of frame
characters is determined during the
negotiation stage.
Address/Control/Information Fields
Special characters must be escaped
FCS : 16 bit CRC-CCITT
EOF - End of frame
Original Data
0xC0
0xC1
0x7D
A
C
Escaped Data
0x7D 0xE0
0x7D 0xE1
0x7D 0x5D
3-4200-D1-2.0-0403
I