Datasheet

772
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
36.7.5.1 IrDA Modulation
For baud rates up to and including 115.2 Kb/s, the RZI modulation scheme is used. “0” is represented by a light pulse of
3/16th of a bit time. Some examples of signal pulse duration are shown in Table 36-12.
Figure 36-34 shows an example of character transmission.
Figure 36-34. IrDA Modulation
36.7.5.2 IrDA Baud Rate
Table 36-13 gives some examples of CD values, baud rate error and pulse duration. Note that the requirement on the
maximum acceptable error of ±1.87% must be met.
Table 36-12. IrDA Pulse Duration
Baud Rate Pulse Duration (3/16)
2.4 Kb/s 78.13 µs
9.6 Kb/s 19.53 µs
19.2 Kb/s 9.77 µs
38.4 Kb/s 4.88 µs
57.6 Kb/s 3.26 µs
115.2 Kb/s 1.63 µs
Bit Period
Bit Period
3
16
Start
Bit
Data Bits
Stop
Bit
0
0
0
0
0
1
11
1
1
Transmitter
Output
TXD
Table 36-13. IrDA Baud Rate Error
Peripheral Clock Baud Rate (Bit/s) CD Baud Rate Error Pulse Time (µs)
3,686,400 115,200 2 0.00% 1.63
20,000,000 115,200 11 1.38% 1.63
32,768,000 115,200 18 1.25% 1.63
40,000,000 115,200 22 1.38% 1.63
3,686,400 57,600 4 0.00% 3.26
20,000,000 57,600 22 1.38% 3.26
32,768,000 57,600 36 1.25% 3.26
40,000,000 57,600 43 0.93% 3.26
3,686,400 38,400 6 0.00% 4.88
20,000,000 38,400 33 1.38% 4.88
32,768,000 38,400 53 0.63% 4.88
40,000,000 38,400 65 0.16% 4.88
3,686,400 19,200 12 0.00% 9.77
20,000,000 19,200 65 0.16% 9.77