Bit
Name
Reset
Access Description
1
Framing and parity errors disable the receiver
22
ERRSDMA
0
RW
Halt DMA on Error
When set, DMA requests will be cleared on framing and parity errors (asynchronous mode only).
Value
Description
0
Framing and parity errors have no effect on DMA requests from the
USART
1
DMA requests from the USART are blocked while the PERR or FERR
interrupt flags are set
21
BIT8DV
0
RW
Bit 8 Default Value
The default value of the 9th bit. If 9-bit frames are used, and an 8-bit write operation is done, leaving the 9th bit unspecified,
the 9th bit is set to the value of BIT8DV.
20
SKIPPERRF
0
RW
Skip Parity Error Frames
When set, the receiver discards frames with parity errors (asynchronous mode only). The PERR interrupt flag is still set.
19
SCRETRANS
0
RW
SmartCard Retransmit
When in SmartCard mode, a NACK'ed frame will be kept in the shift register and retransmitted if the transmitter is still ena-
bled.
18
SCMODE
0
RW
SmartCard Mode
Use this bit to enable or disable SmartCard mode.
17
AUTOTRI
0
RW
Automatic TX Tristate
When enabled, TXTRI is set by hardware whenever the transmitter is idle, and TXTRI is cleared by hardware when trans-
mission starts.
Value
Description
0
The output on U(S)n_TX when the transmitter is idle is defined by
TXINV
1
U(S)n_TX is tristated whenever the transmitter is idle
16
AUTOCS
0
RW
Automatic Chip Select
When enabled, the output on USn_CS will be activated one baud-period before transmission starts, and deactivated when
transmission ends.
15
CSINV
0
RW
Chip Select Invert
Default value is active low. This affects both the selection of external slaves, as well as the selection of the microcontroller
as a slave.
Value
Description
0
Chip select is active low
1
Chip select is active high
14
TXINV
0
RW
Transmitter Output Invert
The output from the USART transmitter can optionally be inverted by setting this bit.
Value
Description
0
Output from the transmitter is passed unchanged to U(S)n_TX
Reference Manual
USART - Universal Synchronous Asynchronous Receiver/Transmitter
silabs.com
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