DocID018909 Rev 11
975/1731
RM0090
Universal synchronous asynchronous receiver transmitter (USART)
1010
7
115.2 KBps
115.108 KBps
8.6875
0.08
115.385
13
0.16
8
230.4 KBps
231.884 KBps
4.3125
0.64
230.769
6.5
0.16
9
460.8 KBps
457.143 KBps
2.1875
0.79
461.538
3.25
0.16
10
921.6 KBps
941.176 KBps
1.0625
2.12
923.077
1.625
0.16
11
2 MBps
NA
NA
NA
NA
NA
NA
12
3 MBps
NA
NA
NA
NA
NA
NA
1. The lower the CPU clock the lower the accuracy for a particular baud rate. The upper limit of the achievable baud rate can
be fixed with these data.
Table 135. Error calculation for programmed baud rates at f
PCLK
= 16 MHz or f
PCLK
= 24 MHz,
oversampling by 16
(1)
(continued)
Oversampling by 16 (OVER8 = 0)
Baud rate
fPCLK
= 16 MHz
fPCLK
= 24 MHz
S.No
Desired
Actual
Value
programmed
in the baud
rate register
% Error =
(Calculated -
Desired) B.rate /
Desired B.rate
Actual
Value
programmed
in the baud
rate register
% Error
Table 136. Error calculation for programmed baud rates at f
PCLK
= 16 MHz or f
PCLK
= 24 MHz,
oversampling by 8
(1)
Oversampling by 8 (OVER8=1)
Baud rate
f
PCLK
= 16 MHz
f
PCLK
= 24 MHz
S.No
Desired
Actual
Value
programmed
in the baud
rate register
% Error =
(Calculated -
Desired) B.rate /
Desired B.rate
Actual
Value
programmed
in the baud
rate register
% Error
1
1.2 KBps
1.2 KBps
1666.625
0
1.2 KBps
2500
0
2
2.4 KBps
2.4 KBps
833.375
0
2.4 KBps
1250
0
3
9.6 KBps
9.598 KBps
208.375
0.02
9.6 KBps
312.5
0
4
19.2 KBps
19.208 KBps
104.125
0.04
19.2 KBps
156.25
0
5
38.4 KBps
38.369 KBps
52.125
0.08
38.4 KBps
78.125
0
6
57.6 KBps
57.554 KBps
34.75
0.08
57.554 KBps
52.125
0.08
7
115.2 KBps
115.108 KBps
17.375
0.08
115.385 KBps
26
0.16
8
230.4 KBps
231.884 KBps
8.625
0.64
230.769 KBps
13
0.16
9
460.8 KBps
457.143 KBps
4.375
0.79
461.538 KBps
6.5
0.16
10
921.6 KBps
941.176 KBps
2.125
2.12
923.077 KBps
3.25
0.16
11
2 MBps
2000 KBps
1
0
2000 KBps
1.5
0
12
3 MBps
NA
NA
NA
3000 KBps
1
0
1. The lower the CPU clock the lower the accuracy for a particular baud rate. The upper limit of the achievable baud rate can
be fixed with these data.