st10f269z1 STMicroelectronics, st10f269z1 Datasheet - Page 96

• Manufacturer Part Number: st10f269z1
• Description: St10f269 16-bit Mcu With Mac Unit, 256k Byte Flash Memory And 12k Byte Ram
• Manufacturer: STMicroelectronics

14 - SERIAL CHANNELS
Asynchronous Mode Baud rates
For asynchronous operation, the Baud rate
generator provides a clock with 16 times the rate
of the established Baud rate. Every received bit is
sampled at the 7th, 8th and 9th cycle of this clock.
The Baud rate for asynchronous operation of
serial channel ASC0 and the required reload
value for a given Baud rate can be determined by
the following formulas:
(S0BRL) represents the content of the reload
register, taken as unsigned 13-bit integer,
(S0BRS) represents the value of bit S0BRS (‘0’ or
‘1’), taken as integer.
Table 28 : Commonly Used Baud Rates by Reload Value and Deviation Errors (PQFP144 devices)
Note: The deviation errors given in the Table 28 are rounded. To avoid deviation errors use a Baud rate
96/184
Baud Rate (Baud)
1 250 000
112 000
56 000
38 400
19 200
9 600
4 800
2 400
1 200
crystal (providing a multiple of the ASC0/SSC sampling frequency).
600
300
153
S0BRS = ‘0’, f
Deviation Error
+1.5% / -7.0%
+1.5% / -3.0%
+1.7% / -1.4%
+0.2% / -1.4%
+0.2% / -0.0%
+0.2% / -0.6%
+0.2% / -0.2%
0.0% / 0.0%
0.1% / 0.0%
0.0% / 0.0%
0.0% / 0.0%
0.0% / 0.0%
CPU
= 40MHz
Reload Value
000A / 000B
1FE8 / 1FE9
0000 / 0000
0015 / 0016
001F / 0020
0040 / 0041
0081 / 0082
0103 / 0104
0207 / 0208
0410 / 0411
0822 / 0823
1045 / 1046
(hexa)
Baud Rate (Baud)
Using the above equation, the maximum Baud
rate can be calculated for any given clock speed.
Baud rate versus reload register value (SOBRS=0
and SOBRS=1) is described in Table 28. and
Table 29
B
S0BRL = (
Async
833 333
112 000
56 000
38 400
19 200
9 600
4 800
2 400
1 200
600
300
102
=
S0BRS = ‘1’, f
16 x [2 + (S0BRS)] x [(S0BRL) + 1]
16 x [2 + (S0BRS)] x B
Deviation Error
+6.3% / -7.0%
+6.3% / -0.8%
+3.3% / -1.4%
+0.9% / -1.4%
+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%
CPU
f
CPU
f
CPU
= 40MHz
Reload Value
00AC / 00AD
0AD8 / 0AD9
000D / 000E
056B / 056C
1FE8 / 1FE9
002A / 002B
015A / 015B
02B5 / 02B6
0000 / 0000
0006 / 0007
0014 / 0015
0055 / 0056
Async
ST10F269
(hexa)
) - 1