XR21V1410IL-0A-EB Datasheet, PDF (21/28 Pages) Exar Corporation – 1-CH FULL-SPEED USB UART

XR21V1410
REV. 1.3.0
1-CH FULL-SPEED USB UART
3.3.12 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 1.5, UART” on
page 7.
TABLE 14: GPIO MODES
BITS
[2:0]
GPIO0 GPIO1
GPIO2
GPIO3
GPIO4
GPIO5
MODE DESCRIPTION
000 GPIO0 GPIO1 GPIO2 GPIO3 GPIO4 GPIO5 GPIO Mode, All GPIO pins available as GPIO
001 GPIO0 GPIO1 GPIO2 GPIO3 CTS#
RTS# GPIO4 and GPIO5 used for Auto RTS/CTS HW
Flow Control
010 GPIO0 GPIO1 DSR#
DTR#
GPIO4 GPIO5 GPIO2 and GPIO3 used for Auto DTR/DSR HW
Flow Control
011 GPIO0 GPIO1 GPIO2 GPIO3 GPIO4 XCVR GPIO5 used for Auto Transceiver Enable during
Enable Transmit
100 GPIO0 GPIO1 GPIO2 GPIO3 GPIO4 XCVR GPIO5 used for Auto Transceiver Enable after
Enable address match (See FLOW_CONTROL mode 4).
GPIO_MODE[3]: Transceiver Enable Polarity
• Logic 0 = GPIO5 Low for TX
• Logic 1 = GPIO5 High for TX
GPIO_MODE[7:4]: Reserved
These register bits are reserved. When writing to these bits, the value should be ’0’. When reading from these
bits, they are undefined and should be ignored.
3.3.13 GPIO_DIRECTION Register Description (Read/Write)
This register controls the direction of the GPIO if it is not controlled by the GPIO_MODE register.
GPIO_DIRECTION[5:0]: GPIOx Direction
• Logic 0 = GPIOx is an input.
• Logic 1 = GPIOx is an output.
GPIO_DIRECTION[7:6]: Reserved
These register bits are reserved and should be ’0’.
3.3.14 GPIO_INT_MASK Register Description (Read/Write)
Enables / disables generation of a USB interrupt packet at the change of state of GPIO pins when they are
configured as inputs.
GPIO_INT_MASK[5:0]: GPIOx Interrupt Mask
• Logic 0 = A change on this input causes the device to generate an interrupt packet.
• Logic 1 = A change on this input does not cause the device to generate an interrupt packet.
GPIO_INT_MASK[7:6]: Reserved
These register bits are reserved and should be ’0’.
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