at91rm3400 ATMEL Corporation, at91rm3400 Datasheet - Page 288

• Manufacturer Part Number: at91rm3400
• Description: Atmel Advanced At91 Arm Microcontroller
• Manufacturer: ATMEL Corporation

IrDA Modulation
IrDA Baud Rate
288
AT91RM3400
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 51..
Table 51. IrDA Pulse Duration
Figure 112 shows an example of character transmission.
Figure 112. IrDA Modulation
Table 52 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 52. 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
32 768 000
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
38 400
Pulse Duration
(3/16)
78.13 µs
19.53 µs
9.77 µs
4.88 µs
3.26 µs
1.63 µs
Bit Period
Start
Bit
0
1
CD
2
11
18
22
4
22
36
43
6
33
53
0
1
Data Bits
0
0
Baud rate Error
0.00%
1.38%
1.25%
1.38%
0.00%
1.38%
1.25%
0.93%
0.00%
1.38%
0.63%
1
1
16
3
0
Bit Period
Start
Bit
Pulse time
1.63
1.63
1.63
1.63
3.26
3.26
3.26
3.26
4.88
4.88
4.88
1
1790A–ATARM–11/03