XR18W750 ON Semiconductor, XR18W750 Datasheet - Page 23

• Manufacturer Part Number: XR18W750
• Manufacturer: ON Semiconductor

REV. 1.0.0
ISR[0]: Interrupt Status
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ISR[3:1]: Interrupt Status
These bits indicate the source for a pending interrupt at interrupt priority levels (See Interrupt Source
ISR[4]: Reserved
ISR[5]: RTS#/CTS# Interrupt Status
This bit is enabled when EFR bit-4 is set to a logic 1. ISR bit-5 indicates that the CTS# or RTS# has been de-
asserted.
ISR[7:6]: FIFO Enable Status
These bits are set to a logic 0 when the FIFOs are disabled. They are set to a logic 1 when the FIFOs are
enabled.
This register is used to enable the FIFOs, clear the FIFOs, set the transmit/receive FIFO trigger levels, and
select the DMA mode. The DMA, and FIFO modes are defined as follows:
FCR[0]: TX and RX FIFO Enable
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•
FCR[1]: RX FIFO Reset
This bit is only active when FCR bit-0 is a ‘1’.
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•
5.5
Logic 0 = An interrupt is pending and the ISR contents may be used as a pointer to the appropriate interrupt
service routine.
Logic 1 = No interrupt pending (default condition).
Logic 0 = Disable the transmit and receive FIFO (default).
Logic 1 = Enable the transmit and receive FIFOs. This bit must be set to logic 1 when other FCR bits are
written or they will not be programmed.
Logic 0 = No receive FIFO reset (default)
Logic 1 = Reset the receive FIFO pointers and FIFO level counter logic (the receive shift register is not
cleared or altered). This bit will return to a logic 0 after resetting the FIFO.
FIFO Control Register (FCR) - Write-Only
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WIRELESS UART CONTROLLER
XR18W750
Table
9).