RM0016 Universal asynchronous receiver transmitter (UART)
Doc ID 14587 Rev 8 345/449
Impact of clock deviation on maximum baud rate
The choice of the nominal baud rate (UARTDIVNOM) will influence both the quantization
error (DQUANT) and the measurement error (DMEAS). The worst case occurs for
UARTDIVMIN.
Consequently, at a given CPU frequency, the maximum possible nominal baud rate
(LPRMIN) should be chosen with respect to the maximum tolerated deviation given by the
equation:
DTRA + 1 / (2*UARTDIVMIN) + DREC + DTCL < 3.75%
Example:
A nominal baud rate of 20 Kbits/s at TCPU = 125 ns (8 MHz) leads to UARTDIVNOM = 25d.
UARTDIVMIN = 25 - 0.15*25 = 21.25
DQUANT = 1 / (2*UARTDIVMIN) = 0.0015%
Figure 137. Bit sampling in reception mode
22.4.4 LIN mode selection
RDI LINE
Sample
clock
1234567891011
12
13 14 15 16
sampled values
One bit time
6/16
7/16
7/16
Table 58. LIN mode selection
LINE LSLV LASE Meaning
0
00
LIN mode disabled
1
LIN Master Mode
1
0
LIN Slave Mode
with Automatic resynchronization disabled
1
LIN Slave Mode
with Automatic resynchronization enabled
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