XR21B1422 Datasheet, PDF (28/60 Pages) Exar Corporation – Enhanced 2-Ch Full-Speed USB UART

XR21B1422
GPIO_CLEAR (0x00F) - Write-Only
This register controls pins configured as GPIO outputs. Pins configured for alternate functions via the GPIO_MODE register
are not controlled by this register. Writing a ’1’ to a bit position in this register clears the corresponding GPIO output low.
Writing a ’0’ to a bit has no effect. For GPIO pins configured as inputs via the GPIO_DIRECTION register, this register has
no effect.
Bit
15:10
9:0
Default
0
Reserved
These bits are reserved and should be ‘0.’
0
GPIO Set of GPIO[9:0]
0: No effect on GPIOx pin.
1: GPIOx output is cleared to a ’0’.
Description
GPIO_STATE (0x010) - Read/Write
Bit
15:10
9:0
Default
Description
0
Reserved
These bits are reserved and should be ‘0.’
0
GPIO State of GPIO[9:0]
Read returns state of all pins, whether GPIO or alternate function, input or output
0: Write clears the respective GPIO output to a ’0’
1: Write sets the respective GPIO output to a ’1’
GPIO_INT_MASK (0x011) - Read/Write
This register is used to configure whether a change in pin state causes the device to generate a USB interrupt packet. Note
that the GPIO status register will still report the GPIO pin state when read, and if an interrupt packet is formed due to other
interrupt trigger, the interrupt packet will contain the current state of the pin. This register applies to all inputs pins irrespec-
tive of if they are configured as GPIO or alternate functions.
Bit
15:10
9:0
Default
Description
0
0x100
Reserved
These bits are reserved and should be written as ‘0’.
GPIO Interrupt Mask of GPIO[9:0]
0: A change in the input pin's state causes the device to generate an interrupt packet
1: A change in the input pin's state does not cause the device to generate an interrupt packet
© 2014 Exar Corporation
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Rev 1A