Datasheet

547
11011B–ATARM–21-Feb-12
SAM3N
547
11011B–ATARM–21-Feb-12
SAM3N
• Configure the TXD pin as PIO and set it as an output to 0 (to avoid LED emission). Disable
the internal pull-up (better for power consumption).
• Receive data
30.7.5.1 IrDA Modulation
For baud rates up to and including 115.2 Kbits/sec, 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 30-12.
Figure 30-24 shows an example of character transmission.
Figure 30-24. IrDA Modulation
30.7.5.2 IrDA Baud Rate
Table 30-13 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 30-12. 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 30-13. IrDA Baud Rate Error
Peripheral Clock Baud Rate CD Baud Rate Error Pulse Time
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