xr20m1280 Exar Corporation, xr20m1280 Datasheet - Page 32

• Manufacturer Part Number: xr20m1280
• Description: I2c/spi Uart With 128-byte Fifo And Integrated Level Shifters
• Manufacturer: Exar Corporation

XR20M1280
I2C/SPI UART WITH 128-BYTE FIFO AND INTEGRATED LEVEL SHIFTERS
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3.4.1
3.4.2
P
LSR is by any of the LSR bits 1, 2, 3 and 4.
RXRDY is by RX trigger level.
RXRDY Time-out is by a 4-char plus 12 bits delay timer.
TXRDY is by TX trigger level or TX FIFO empty.
MSR is by any of the MSR bits 0, 1, 2 and 3.
Receive Xon/Xoff/Special character is by detection of a Xon, Xoff or Special character.
CTS# is when the remote transmitter toggles the input pin (from LOW to HIGH) during auto CTS flow control.
RTS# is when its receiver toggles the output pin (from LOW to HIGH) during auto RTS flow control.
Wakeup interrupt is generated when the M1280 wakes up from the sleep mode.
GPIO interrupt is generated when a GPIO input has been asserted (polarity selected by GPIOINV register)
LSR interrupt is cleared by a read to the LSR register.
RXRDY interrupt is cleared by reading data until FIFO falls below the trigger level.
RXRDY Time-out interrupt is cleared by reading RHR.
TXRDY interrupt is cleared by a read to the ISR register or writing to THR.
MSR interrupt is cleared by a read to the MSR register.
Xon or Xoff interrupt is cleared by a read to the ISR register.
Special character interrupt is cleared by a read to ISR register or after next character is received.
RTS# and CTS# flow control interrupts are cleared by a read to the MSR register.
Wakeup interrupt is cleared by a read to ISR register.
GPIO interrupt is cleared by a read to the GPIOLVL register
RIORITY
L
EVEL
1
2
3
4
5
6
7
-
Interrupt Generation:
Interrupt Clearing:
B
IT
0
0
0
0
0
0
1
0
-5
B
IT
0
0
0
0
0
1
0
0
-4
ISR R
B
T
EGISTER
IT
0
1
0
0
0
0
0
0
ABLE
-3
11: I
B
S
IT
TATUS
1
1
1
0
0
0
0
0
-2
NTERRUPT
B
PRELIMINARY
B
ITS
IT
1
0
0
1
0
0
0
0
-1
S
OURCE AND
32
B
IT
0
0
0
0
0
0
0
1
-0
LSR (Receiver Line Status Register)
RXRDY (Receive Data Time-out)
RXRDY (Received Data Ready)
TXRDY (Transmit Ready)
MSR (Modem Status Register)
RXRDY (Received Xon, Xoff or Special character)
CTS#, RTS# change of state
None (default) or Wakeup interrupt
P
RIORITY
L
EVEL
S
OURCE OF INTERRUPT
REV. P1.1.1