xr16l784iv Exar Corporation, xr16l784iv Datasheet - Page 28

• Manufacturer Part Number: xr16l784iv
• Description: High Performance 2.97v To 5.5v Quad Uart
• Manufacturer: Exar Corporation

XR16L784
HIGH PERFORMANCE 2.97V TO 5.5V QUAD UART
IER[0]: RHR Interrupt Enable
The receive data ready interrupt will be issued when RHR has a data character in the non-FIFO mode or when
the receive FIFO has reached the programmed trigger level in the FIFO mode.
•
•
IER[1]: THR Interrupt Enable
This interrupt is associated with bit-5 in the LSR register. An interrupt is issued whenever the THR becomes
empty or when data in the TX FIFO falls below the programmed trigger level.
•
•
IER[2]: Receive Line Status Interrupt Enable
If any of the LSR register bits 1, 2, 3 or 4 is a logic 1, it will generate an interrupt to inform the host controller
about the error status of the current data byte in FIFO. LSR bits 1-4 generate an interrupt immediately when
the character has been received.
•
•
IER[3]: Modem Status Interrupt Enable
•
•
IER[4]: Reserved
IER[5]: Xoff Interrupt Enable (requires EFR bit-4=1)
•
•
IER[6]: RTS# Output Interrupt Enable (requires EFR bit-4=1)
•
•
IER[7]: CTS# Input Interrupt Enable (requires EFR bit-4=1)
•
•
The UART provides multiple levels of prioritized interrupts to minimize external software interaction. The
Interrupt Status Register (ISR) provides the user with six interrupt status bits. Performing a read cycle on the
ISR will give the user the current highest pending interrupt level to be serviced, others queue up for next
service. No other interrupts are acknowledged until the pending interrupt is serviced. The Interrupt Source
Table,
associated with each of these interrupt levels.
4.4
Logic 0 = Disable the receive data ready interrupt (default).
Logic 1 = Enable the receiver data ready interrupt.
Logic 0 = Disable Transmit Holding Register empty interrupt (default).
Logic 1 = Enable Transmit Holding Register empty interrupt.
Logic 0 = Disable the receiver line status interrupt (default).
Logic 1 = Enable the receiver line status interrupt.
Logic 0 = Disable the modem status register interrupt (default).
Logic 1 = Enable the modem status register interrupt.
Logic 0 = Disable the software flow control, receive Xoff interrupt (default).
Logic 1 = Enable the software flow control, receive Xoff interrupt. See Software Flow Control section for
details.
Logic 0 = Disable the RTS# interrupt (default).
Logic 1 = Enable the RTS# interrupt. The UART issues an interrupt when the RTS# pin makes a transition.
Logic 0 = Disable the CTS# interrupt (default).
Logic 1 = Enable the CTS# interrupt. The UART issues an interrupt when CTS# pin makes a transition.
Table 13
Interrupt Status Register (ISR) - Read Only
, shows the data values (bit 0-5) for the six prioritized interrupt levels and the interrupt sources
.
28
xr
REV. 1.2.2