XR21B1411IL-0A-EB Datasheet, PDF (16/30 Pages) Exar Corporation – ENHANCED 1-CH FULL-SPEED USB UART

XR21B1411
ENHANCED 1-CH FULL-SPEED USB UART
FLOW_CONTROL[2:0]: Flow control mode select
TABLE 6: FLOW CONTROL MODE SELECTION
REV. 1.2.0
MODE BIT-2 BIT-1 BIT-0
MODE DESCRIPTION
0
0
0
0 No flow control, no address matching.
1
0
0
1 HW flow control enabled. Auto RTS/CTS or DTR/DSR must be selected by
GPIO_MODE.
2
0
1
0 SW flow control enabled
3
0
1
1 Multidrop mode - RX only after address match, TX independent. (Typically
used with GPIO_MODE 3)
4
1
0
0 Multidrop mode - RX / TX only after address match. (Typically used with GPI-
O_MODE 4)
FLOW_CONTROL[3]: Half-Duplex Mode
 Logic 0 = Normal (full-duplex) mode. The UART can transmit and receive data at the same time.
 Logic 1 = Half-duplex Mode. In half-duplex mode, any data on the RX pin is ignored when the UART is
transmitting data.
FLOW_CONTROL[11:4]: Reserved
These bits are reserved and should remain ’0’.
3.1.1.8
XON_CHAR Register Description (Read / Write - Default 0x17)
The XON_CHAR stores the XON character that is used in the Automatic Software Flow control.
XON_CHAR[7:0]: XON Character
In Automatic Software Flow control mode, the UART will resume data transmission when the XON character
has been received.
For behavior in the Address Match mode, see “Section 1.3.7, Multidrop mode with address matching” on
page 9.
XON_CHAR[11:8]: Reserved
These bits are reserved and should remain ’0’.
3.1.1.9
XOFF_CHAR Register Description (Read / Write - Default 0x19)
The XOFF_CHAR stores the XOFF character that is used in the Automatic Software Flow control.
XOFF_CHAR[7:0]: XOFF Character
In Automatic Software Flow control mode, the UART will suspend data transmission when the XOFF character
has been received.
For behavior in the Address Match mode, see “Section 1.3.7, Multidrop mode with address matching” on
page 9.
XOFF_CHAR[11:8]: Reserved
These bits are reserved and should remain ’0’.
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