ST10F269Z2QX Datasheet, PDF (94/161 Pages) STMicroelectronics – 16-BIT MCU WITH MAC UNIT, 256K BYTE FLASH MEMORY AND 12K BYTE RAM

ST10F269Z2Qx
Synchronous Mode Baud Rates
For synchronous operation, the Baud rate
generator provides a clock with 4 times the rate of
the established Baud rate. The Baud rate for
synchronous operation of serial channel ASC0
can be determined by the following formula:
(S0BRL) represents the content of the reload
register, taken as unsigned 13-bit integers,
(S0BRS) represents the value of bit S0BRS (‘0’ or
‘1’), taken as integer.
f_CPU
B_Sync = _{4 x [2 + (S0BRS)] x [(S0BRL) + 1]}
f_CPU
S0BRL = (
)-1
4 x [2 + (S0BRS)] x B_Sync
Using the above equation, the maximum Baud
rate can be calculated for any clock speed as
given in Table 24.
Table 24 : Commonly Used Baud Rates by Reload Value and Deviation Errors
S0BRS = ‘0’, f_CPU = 40MHz
S0BRS = ‘1’, f_CPU = 40MHz
Reload Value
Reload Value
Baud Rate (Baud) Deviation Error
Baud Rate (Baud) Deviation Error
(hexa)
(hexa)
5 000 000
0.0% / 0.0%
0000 / 0000
3 333 333
0.0% / 0.0%
0000 / 0000
112 000
+1.5% / -0.8% 002B / 002C
112 000
+2.6% / -0.8% 001C / 001D
56 000
+0.3% / -0.8%
0058 / 0059
56 000
+0.9% / -0.8% 003A / 003B
38 400
+0.2% / -0.6%
0081 / 0082
38 400
+0.9% / -0.2% 0055 / 0056
19 200
+0.2% / -0.2%
0103 / 0104
19 200
+0.4% / -0.2% 00AC / 00AD
9 600
+0.2% / -0.0% 0207 / 0208
9 600
+0.1% / -0.2% 015A / 015B
4 800
+0.1% / -0.0% 0410 / 0411
4 800
+0.1% / -0.1% 02B5 / 02B6
2 400
0.0% / 0.0%
0822 / 0823
2 400
+0.1% / -0.0% 056B / 056C
1 200
0.0% / 0.0%
1045 / 1046
1 200
0.0% / 0.0%
0AD8 / 0AD9
900
0.0% / 0.0%
15B2 / 15B3
600
0.0% / 0.0%
15B2 / 15B3
612
0.0% / 0.0%
1FE8 / 1FE9
407
0.0% / 0.0%
1FFD / 1FFE
Note: The deviation errors given in the Table 24 are rounded. To avoid deviation errors use a Baud rate
crystal (providing a multiple of the ASC0/SSC sampling frequency)
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