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Chapter 32 USART (LIN / FIFO)
6.USART Baud Rates
■ Suggested Division Ratios for different machine speeds and baud rates
The following settings are suggested for different MCU clock speeds and baud rates:
■ Counting Example
Assume the reload value is 832. The figure 6-2 demonstrates the behavior of the both Reload Counters:
Table 6-1 Suggested Baud Rates and reload values at different machine speeds.
Baud
rate
8 MHz 10 MHz 16 MHz 20 MHz 24 MHz 32 MHz
value
%
dev.
value
%
dev.
value
%
dev.
value
%
dev.
value
%
dev.
value
%
dev.
2M30407090110150
1M7090150190230310
500000 15 0 19 0 31 0 39 0 47 0 63 0
460800 --------51-0.16 - -
250000 31 0 39 0 63 0 79 0 95 0 127 0
230400 ------860.22 103 -0.16 138 -0.08
153600 51 -0.16 64 -0.16 103 -0.16 129 -0.16 155 -0.16 207 0.16
125000 63 0 79 0 127 0 159 0 191 0 255 0
115200 - - 86 0.22 138 0.08 173 0.22 207 -0.16 278 -0.08
76800 103 -0.16 129 -0.16 207 -0.16 259 -0.16 311 -0.16 416 0.08
57600 138 0.08 173 0.22 277 0.08 346 -0.06 416 0.08 555 0.08
38400 207 -0.16 259 -0.16 416 0.08 520 0.03 624 0 832 -0.04
28800 277 0.08 346 <0.01 554 -0.01 693 -0.06 832 -0.03 1110 -0.01
19200 416 0.08 520 0.03 832 -0.03 1041 0.03 1249 0 1666 0.02
10417 767 <0.01 959 <0.01 1535 <0.01 1919 <0.01 2303 <0.01 3071 <0.01
9600 832 0.04 1041 0.03 1666 0.02 2083 0.03 2499 0 3332 0.01
7200 1110 <0.01 1388 <0.01 2221 <0.01 2777 <0.01 3332 <0.01 4443 -0.01
4800 1666 0.02 2082 -0.02 3332 <0.01 4166 <0.01 4999 0 6666 <0.01
2400 3332 <0.01 4166 <0.01 6666 <0.01 8332 <0.01 9999 0 13332 <0.01
1200 6666 <0.01 8334 0.02 13332 <0.01 16666 <0.01 19999 0 26666 <0.01
600 13332 <0.01 16666 <0.01 26666 <0.01 ----
300 26666 <0.01 --------