Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Data Sheet
Product codes
AT91SAM9M10-G45-EK
498
SAM9M10 [DATASHEET]
6355F–ATARM–12-Mar-13
The receiver and the transmitter must be enabled or disabled according to the direction of the transmission to be
managed.
managed.
To receive IrDA signals, the following needs to be done:
• Disable TX and Enable RX
• Configure the TXD pin as PIO and set it as an output at 0 (to avoid LED emission). Disable the internal pull-up
(better for power consumption).
• Receive data
31.7.5.1
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
light pulse of 3/16th of a bit time. Some examples of signal pulse duration are shown in
Figure 31-34.
IrDA Modulation
31.7.5.2
IrDA Baud Rate
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 31-12.
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
1
1
1
1
Transmitter
Output
TXD
Table 31-13.
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