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XR21V1414 Datasheet, PDF (22/26 Pages) Exar Corporation – 4-CH FULL-SPEED USB UART
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XR21V1414
4-CH FULL-SPEED USB UART
REV. 1.0.0
ERROR_STATUS[4]: Framing Error
• Logic 0 = No framing error
• Logic 1 = A framing error has been detected (clears after read). A framing error occurs when a stop bit is not
present when it is expected.
ERROR_STATUS[5]: Parity Error
• Logic 0 = No parity error
• Logic 1 = A parity error has been detected (clears after read).
ERROR_STATUS[6]: Overrun Error
• Logic 0 = No overrun error
• Logic 1 = An overrun error has been detected (clears after read). An overrun error occurs when the RX FIFO
is full and another byte of data is received.
ERROR_STATUS[7]: Break Status
• Logic 0 = Break condition is no longer present.
• Logic 1 = Break condition is currently being detected.
3.3.9 TX_BREAK Register Description (Read/Write)
Writing a non-zero value to this register causes a break condition to be generated continuously until the
register is cleared. If data is being shifted out of the TX pin, the data will be completed shifted out before the
break condition is generated.
3.3.10 XCVR_EN_DELAY Register Description (Read/Write)
XCVR_EN_DELAY[3:0]: Turn-around delay
This is the number of bit times to wait before changing the direction of the transceiver from transmit to receive
when half-duplex mode is enabled.
XCVR_EN_DELAY[3:0]: Reserved
These bits are reserved and should be ’0’.
3.3.11 GPIO_MODE Register Description (Read/Write)
GPIO_MODE[2:0]: GPIO Mode Select
There are 4 modes of operation for the GPIOs. The descriptions can be found in “Section 1.4, UART” on
page 9.
TABLE 13: GPIO MODES
BITS
[2:0]
GPIO0 GPIO1 GPIO2
GPIO3
GPIO4 GPIO5
MODE DESCRIPTION
000 GPIO0 GPIO1 GPIO2 GPIO3 GPIO4 GPIO5 GPIO Mode
001 GPIO0 GPIO1 GPIO2 GPIO3 CTS# RTS# Auto RTS/CTS HW Flow Control
010 GPIO0 GPIO1 DSR# DTR# GPIO4 GPIO5 Auto DTR/DSR HW Flow Control
011 GPIO0 GPIO1 GPIO2 GPIO3 GPIO4 XCVR Multidrop Mode with Auto Half-Duplex Trans-
Enable ceiver Control
100 GPIO0 GPIO1 GPIO2 GPIO3 GPIO4 XCVR Multidrop Mode with Auto TX Enable
Enable
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