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CHAPTER 20 UART2, UART3
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Using LIN operation mode 3
The LIN features are available in mode 3 (transmitting, receiving synch break), but using mode 3 sets the
UART2, UART3 data format automatically to LIN format (8N1, LSB first). Note, that the length of the
synch break for transmission is variable but for reception it is fixed 11-bit times.
Note:
During LIN operation, please set SCES bit of ESCR2/ESCR3 register to "0".
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Changing operation settings
It is strongly recommended to reset UART2, UART3 after changing operation settings. Particularly if (for
example) start-/stop-bits added to or removed from the data format.
Note:
If settings in the Serial Mode Register (SMR2/SMR3) are desired, it is not useful to set the UPCL bit
at the same time to reset UART2, UART3. The correct operation settings are not guaranteed in this
case. Thus it is recommended to set the bits of the SMR2/SMR3 and then to set them again plus the
UPCL bit.
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LIN slave settings
Set the baud rate before receiving the first LIN synch break for the slave operation. Otherwise, duration of
the synch break can not be correctly checked against the minimum requirement of the LIN specification (13
master bit time and 11 slave bit time).
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Software compatibility
Although UART2, UART3 is similar to other UARTs in other microcontrollers it is not software
compatible to them. The programming models may be the same, but the structure of the registers differ.
Furthermore the setting of the baud rate is now determined by a reload value instead of selecting a
predefined value.
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Bus idle function
The Bus Idle Function cannot be used in synchronous mode 2 and SSM=0.
402
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