XR21V1414 Datasheet, PDF (21/26 Pages) Exar Corporation – 4-CH FULL-SPEED USB UART

XR21V1414
REV. 1.0.0
4-CH FULL-SPEED USB UART
FLOW_CONTROL[2:0]: Flow control mode select
TABLE 12: FLOW CONTROL MODE SELECTION
BIT-2
BIT-1
BIT-0
MODE DESCRIPTION
0
0
0
No flow control.
0
0
1
HW flow control enabled
0
1
0
SW flow control enabled
0
1
1
Multidrop mode with Automatic Half-Duplex Transceiver control
1
0
0
Multidrop mode with Automatic Transmitter Enable
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[7:4]: Reserved
These bits are reserved and should remain ’0’.
3.3.7 XON_CHAR, XOFF_CHAR Register Descriptions (Read/Write)
The XON_CHAR and XOFF_CHAR registers store the XON and XOFF characters, respectively, that are 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 1.4.7, Multidrop Mode with Automatic Half-Duplex
Transceiver Control” on page 12.
For behavior in the Address Match with TX Flow Control mode, see “Section 1.4.8, Multidrop Mode with
Automatic Transmitter Enable” on page 12.
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 1.4.7, Multidrop Mode with Automatic Half-Duplex
Transceiver Control” on page 12.
For behavior in the Address Match with TX Flow Control mode, see “Section 1.4.8, Multidrop Mode with
Automatic Transmitter Enable” on page 12.
3.3.8 ERROR_STATUS Register Description - Read-only
This register reports any errors that may have occurred on the line such as break, framing, parity and overrun.
ERROR_STATUS[2:0]: Reserved
These bits are reserved. Any values read from these bits should be ignored.
ERROR_STATUS[3]: Break error
• Logic 0 = No break condition
• Logic 1 = A break condition has been detected (clears after read).
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