ATMEGA2561V ATMEL [ATMEL Corporation], ATMEGA2561V Datasheet - Page 232

• Manufacturer Part Number: ATMEGA2561V
• Description: 8-bit Microcontroller with 64K/128K/256K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Examples of Baud Rate
Setting
Table 109. Examples of UBRRn Settings for Commonly Used Oscillator Frequencies
1.
232
Baud
Rate
(bps)
2400
4800
9600
14.4k
19.2k
28.8k
38.4k
57.6k
76.8k
115.2k
230.4k
250k
Max.
(1)
UBRR = 0, Error = 0.0%
ATmega640/1280/1281/2560/2561
UBRR
25
12
6
3
2
1
1
0
–
–
–
–
62.5 kbps
U2Xn = 0
f
Error
-18.6%
osc
-7.0%
8.5%
8.5%
0.2%
0.2%
8.5%
8.5%
–
–
–
–
= 1.0000 MHz
UBRR
51
25
12
8
6
3
2
1
1
0
–
–
U2Xn = 1
125 kbps
For standard crystal and resonator frequencies, the most commonly used baud rates for
asynchronous operation can be generated by using the UBRR settings in Table 109 to
Table 112. UBRR values which yield an actual baud rate differing less than 0.5% from
the target baud rate, are bold in the table. Higher error ratings are acceptable, but the
Receiver will have less noise resistance when the error ratings are high, especially for
large serial frames (see “Asynchronous Operational Range” on page 224). The error
values are calculated using the following equation:
Error
-18.6%
-3.5%
-7.0%
0.2%
0.2%
0.2%
8.5%
8.5%
8.5%
8.5%
–
–
UBRR
47
23
11
7
5
3
2
1
1
0
–
–
115.2 kbps
U2Xn = 0
Error[%]
f
Error
-25.0%
osc
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
–
–
= 1.8432 MHz
=
UBRR
⎛
⎝
BaudRate
------------------------------------------------------- - 1
95
47
23
15
11
7
5
3
2
1
0
–
230.4 kbps
U2Xn = 1
BaudRate
Error
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
Closest Match
–
UBRR
51
25
12
–
8
6
3
2
1
1
0
–
–
U2Xn = 0
125 kbps
⎞
⎠
•
100%
f
Error
-18.6%
osc
-3.5%
-7.0%
0.2%
0.2%
0.2%
8.5%
8.5%
8.5%
8.5%
–
–
= 2.0000 MHz
UBRR
103
16
12
51
25
8
6
3
2
1
–
0
U2Xn = 1
250 kbps
2549K–AVR–01/07
Error
-3.5%
-7.0%
2.1%
0.2%
8.5%
8.5%
8.5%
0.2%
0.2%
0.2%
0.0%
–