AT91SAM7S32-AI ATMEL [ATMEL Corporation], AT91SAM7S32-AI Datasheet - Page 286

• Manufacturer Part Number: AT91SAM7S32-AI
• Description: AT91 ARM Thumb-based Microcontrollers
• Manufacturer: ATMEL [ATMEL Corporation]

IrDA Modulation
IrDA Baud Rate
286
AT91SAM7S32 Preliminary
The receiver and the transmitter must be enabled or disabled according to the direction of the
transmission to be managed.
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 66.
Table 66. IrDA Pulse Duration
Figure 122 shows an example of character transmission.
Figure 122. IrDA Modulation
Table 67 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 67. IrDA Baud Rate Error
Baud Rate
2.4 Kb/s
9.6 Kb/s
19.2 Kb/s
38.4 Kb/s
57.6 Kb/s
115.2 Kb/s
Peripheral Clock
3 686 400
20 000 000
32 768 000
40 000 000
3 686 400
20 000 000
32 768 000
40 000 000
3 686 400
20 000 000
Transmitter
Output
TXD
Baud Rate
115 200
115 200
115 200
115 200
57 600
57 600
57 600
57 600
38 400
38 400
Bit Period
Start
Bit
0
1
0
1
CD
11
18
22
22
36
43
33
2
4
6
Pulse Duration (3/16)
78.13 µs
19.53 µs
9.77 µs
4.88 µs
3.26 µs
1.63 µs
Data Bits
0
0
Baud Rate Error
1
0.00%
1.38%
1.25%
1.38%
0.00%
1.38%
1.25%
0.93%
0.00%
1.38%
1
16
3
0
Bit Period
Start
6071A–ATARM–28-Oct-04
Bit
1
Pulse Time
1.63
1.63
1.63
1.63
3.26
3.26
3.26
3.26
4.88
4.88