XR21B1422IL40-0A Datasheet, PDF (32/60 Pages) Exar Corporation – Enhanced 2-Ch Full-Speed USB UART

XR21B1422
LOOPBACK (0x016) - Read/Write
This register is used to configure the internal UART loopback.
Bit
15:3
2
1
0
Default
Description
0
Reserved
These bits are reserved and should be written as ‘0’.
0
DTR_DSR
When this bit is set, DTR is looped back to DSR.
0: Disable loopback.
1: Enable loopback.
0
RTS_CTS
When this bit is set, RTS is looped back to CTS.
0: Disable loopback.
1: Enable loopback.
0
TX_RX
When this bit is set, all transmitted UART data is internally looped back to the UART receiver. Note that when internal loop-
back is enabled, external TX data will be disabled and RX data will be ignored.
0: Disable loopback.
1: Enable loopback.
IR_MODE (0x017) - Read/Write
Bit
15:3
2
1
0
Default
Description
0
Reserved
These bits are reserved and should be written as ‘0’.
0
TX_PULSE
This bit controls the pulse width of the TX data
0: TX pulse width is 3/16th of the bit period
1: TX pulse width is 4/16th of the bit period
0
RX_INVERT
This bit inverts the RX data for IR devices that do not conform to standard.
0: RX data is not inverted
1: RX data is inverted
0
EN
This register bit is used to enable the infrared (IR) mode.
0: Disable IR mode.
1: Enable IR mode.
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