DocID018909 Rev 11
979/1731
RM0090
Universal synchronous asynchronous receiver transmitter (USART)
1010
9.
921.6 KBps
909.091 KBps
4.1250
1.36%
923.077 KBps 8.1250
0.16%
10.
1.792 MBps
1.7647 MBps
2.1250
1.52%
1.8182 MBps
4.1250
1.46%
11.
1.8432 MBps
1.8750 MBps
2.0000
1.73%
1.8182 MBps
4.1250
1.36%
12.
3.584 MBps
3.7500 MBps
1.0000
4.63%
3.5294 MBps
2.1250
1.52%
13.
3.6864 MBps
3.7500 MBps
1.0000
1.73%
3.7500 MBps
2.0000
1.73%
14.
7.168 MBps
NA
NA
NA
7.5000 MBps
1.0000
4.63%
15.
7.3728 MBps
NA
NA
NA
7.5000 MBps
1.0000
1.73%
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.
2. Only USART1 and USART6 are clocked with PCLK2. Other USARTs are clocked with PCLK1. Refer to the device
datasheets for the maximum values for PCLK1 and PCLK2.
Table 140. Error calculation for programmed baud rates at f
PCLK
= 30 MHz or f
PCLK
= 60 MHz,
oversampling by 8
(1)
(2)
(continued)
Oversampling by 8 (OVER8=1)
Baud rate
f
PCLK
= 30 MHz
f
PCLK
=60 MHz
S.No
Desired
Actual
Value
programme
d in the
baud rate
register
% Error =
(Calculated -
Desired)B.Rate
/Desired B.Rate
Actual
Value
programmed
in the baud
rate register
%
Error
Table 141. Error calculation for programmed baud rates at f
PCLK
= 42 MHz or f
PCLK
= 84 Hz,
oversampling by 16
(1)(2)
Oversampling by 16 (OVER8=0)
Baud rate
f
PCLK
= 42 MHz
f
PCLK
= 84 MHz
S.No
Desired
Actual
Value
programme
d 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
2187.5
0
1.2 KBps
4375
0
2
2.4 KBps
2.4 KBps
1093.75
0
2.4 KBps
2187.5
0
3
9.6 KBps
9.6 KBps
273.4375
0
9.6 KBps
546.875
0
4
19.2 KBps
19.195 KBps
136.75
0.02
19.2 KBps
273.4375
0
5
38.4 KBps
38.391 KBps
68.375
0.02
38.391 KBps
136.75
0.02
6
57.6 KBps
57.613 KBps
45.5625
0.02
57.613 KBps
91.125
0.02
7
115.2 KBps
115.068 KBps
22.8125
0.11
115.226 KBps
45.5625
0.02
8
230.4 KBps
230.769 KBps
11.375
0.16
230.137 KBps
22.8125
0.11
9
460.8 KBps
461.538 KBps
5.6875
0.16
461.538 KBps
11.375
0.16
10
921.6 KBps
913.043 KBps
2.875
0.93
923.076 KBps
5.6875
0.93