XR21B1420IL28-0A Datasheet, PDF (30/60 Pages) Exar Corporation – Enhanced 1-Ch Full-Speed USB UART

XR21B1420
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 loopback 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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