Universal synchronous asynchronous receiver transmitter (USART)
RM0090
976/1731
DocID018909 Rev 11
Table 137. Error calculation for programmed baud rates at f
PCLK
= 8 MHz or f
PCLK
= 16 MHz,
oversampling by 16
(1)
Oversampling by 16 (OVER8=0)
Baud rate
f
PCLK
= 8 MHz
f
PCLK
= 16 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.
2.4 KBps
2.400 KBps
208.3125
0.00%
2.400 KBps
416.6875
0.00%
2.
9.6 KBps
9.604 KBps
52.0625
0.04%
9.598 KBps
104.1875
0.02%
3.
19.2 KBps
19.185 KBps
26.0625
0.08%
19.208 KBps
52.0625
0.04%
4.
57.6 KBps
57.554 KBps
8.6875
0.08%
57.554 KBps
17.3750
0.08%
5.
115.2 KBps
115.942 KBps 4.3125
0.64%
115.108 KBps
8.6875
0.08%
6.
230.4 KBps
228.571
KBps
2.1875
0.79%
231.884 KBps
4.3125
0.64%
7.
460.8 KBps
470.588
KBps
1.0625
2.12%
457.143 KBps
2.1875
0.79%
8.
896 KBps
NA
NA
NA
888.889 KBps
1.1250
0.79%
9.
921.6 KBps
NA
NA
NA
941.176 KBps
1.0625
2.12%
10.
1.792 MBps
NA
NA
NA
NA
NA
NA
11.
1.8432 MBps NA
NA
NA
NA
NA
NA
12.
3.584 MBps
NA
NA
NA
NA
NA
NA
13.
3.6864 MBps NA
NA
NA
NA
NA
NA
14.
7.168 MBps
NA
NA
NA
NA
NA
NA
15.
7.3728 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 138. Error calculation for programmed baud rates at f
PCLK
= 8 MHz or f
PCLK
= 16 MHz,
oversampling by 8
(1)
Oversampling by 8 (OVER8=1)
Baud rate
f
PCLK
= 8 MHz
f
PCLK
= 16 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.
2.4 KBps
2.400 KBps
416.625
0.01%
2.400 KBps
833.375
0.00%
2.
9.6 KBps
9.604 KBps
104.125
0.04%
9.598 KBps
208.375
0.02%
3.
19.2 KBps
19.185 KBps
52.125
0.08%
19.208 KBps
104.125
0.04%