Infineon TLE984 QX Series, Руководство пользователя

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User Manual 630 Rev. 1.1
2019-03-18
TLE984xQX
Microcontroller with LIN and Power Switches for Automotive Applications
UART1/UART2
The following formula calculate the final baud rate.
(19.1)
The value of PRE (prescaler) is chosen by the bit field BCON1.BR1_PRE. BR_VALUE represents the contents of
the reload value, taken as unsigned 11-bit integer from the bit field BG1.BG1_BR_VALUE. n/32 is defined by the
fractional divider selection in bit field BGL1.BG1_FD_SEL.
The maximum baud rate that can be generated is limited to
f
sys
/32. Hence, for module clocks of 40 MHz and
25 MHz, the maximum achievable baud rate is 1.25 MBaud and 0.78 MBaud respectively.
Table 332 and Table 333 list various commonly used baud rates together with their corresponding parameter
settings and the deviation errors compared to the intended baud rate.
Table 332 Typical Baud Rates of UART ( f
sys
= 40 MHz)
Baud rate
(
f
sys
= 40 MHz)
PRE Reload Value
(BR_VALUE) Numerator of
Fractional Value
(FD_SEL) Deviation
Error
250.4 kBaud 1 (BR1_PRE = 000) 9(9
H
) 31 (1F
H
) +0.15%
115.2 kBaud 1 (BR1_PRE = 000) 21 (15
H
) 22 (16
H
) +0.06%
20 kBaud 1 (BR1_PRE = 000) 125 (7D
H
) 0 (0
H
) 0.00%
19.2 kBaud 1 (BR1_PRE = 000) 130 (82
H
) 7 (7
H
) -0.01%
9600 Baud 2 (BR1_PRE = 001) 130 (82
H
) 7 (7
H
) -0.01%
4800 Baud 4 (BR1_PRE = 010) 130 (82
H
) 7 (7
H
) -0.01%
2400 Baud 8 (BR1_PRE = 011) 130 (82
H
) 7 (7
H
) -0.01%
Table 333 Typical Baud Rates of UART ( f
sys
= 25 MHz)
Baud rate
(
f
sys
= 25 MHz)
PRE Reload Value
(BR_VALUE) Numerator of
Fractional Value
(FD_SEL) Deviation
Error
115.2 kBaud 1 (BR1_PRE = 000) 13 (D
H
) 18 (12
H
) +0.01%
20 kBaud 1 (BR1_PRE = 000) 78 (4E
H
) 4 (4
H
) 0.00%
19.2 kBaud 1 (BR1_PRE = 000) 81 (51
H
) 12 (C
H
) +0.01%
9600 Baud 2 (BR1_PRE= 001) 81 (51
H
) 12 (C
H
) +0.01%
4800 Baud 4 (BR1_PRE = 010) 81 (51
H
) 12 (C
H
) +0.01%
2400 Baud 8 (BR1_PRE = 011) 81 (51
H
) 12 (C
H
) +0.01%
=
Baud rate
16 PRE (BR )
f
sys
•
•
n
32