ST10F269ZX Datasheet, PDF (99/184 Pages) STMicroelectronics – 16-BIT MCU WITH MAC UNIT, 128K to 256K BYTE FLASH MEMORY AND 12K BYTE RAM

ST10F269
14 - SERIAL CHANNELS
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 30.and Table 31
Table 30 : Commonly Used Baud Rates by Reload Value and Deviation Errors (PQFP144 devices)
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
112 000
56 000
38 400
19 200
9 600
4 800
2 400
1 200
900
612
0.0% / 0.0%
+1.5% / -0.8%
+0.3% / -0.8%
+0.2% / -0.6%
+0.2% / -0.2%
+0.2% / -0.0%
+0.1% / -0.0%
0.0% / 0.0%
0.0% / 0.0%
0.0% / 0.0%
0.0% / 0.0%
0000 / 0000
002B / 002C
0058 / 0059
0081 / 0082
0103 / 0104
0207 / 0208
0410 / 0411
0822 / 0823
1045 / 1046
15B2 / 15B3
1FE8 / 1FE9
3 333 333
112 000
56 000
38 400
19 200
9 600
4 800
2 400
1 200
600
407
0.0% / 0.0%
+2.6% / -0.8%
+0.9% / -0.8%
+0.9% / -0.2%
+0.4% / -0.2%
+0.1% / -0.2%
+0.1% / -0.1%
+0.1% / -0.0%
0.0% / 0.0%
0.0% / 0.0%
0.0% / 0.0%
0000 / 0000
001C / 001D
003A / 003B
0055 / 0056
00AC / 00AD
015A / 015B
02B5 / 02B6
056B / 056C
0AD8 / 0AD9
15B2 / 15B3
1FFD / 1FFE
Note: The deviation errors given in the Table 30 are rounded. To avoid deviation errors use a Baud rate
crystal (providing a multiple of the ASC0/SSC sampling frequency)
99/184