XR16L651CM EXAR [Exar Corporation], XR16L651CM Datasheet - Page 5

• Manufacturer Part Number: XR16L651CM
• Description: 2.25V TO 5.5V UART WITH 32-BYTE FIFO
• Manufacturer: EXAR [Exar Corporation]

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REV. 1.3.0
MODEM OR SERIAL I/O INTERFACE
ANCILLARY SIGNALS
LPT1#
LPT2#
AEN#
CTS#
DTR#
DSR#
N
IRQA
IRQB
IRQC
RTS#
CD#
RI#
RX
S1
S2
S3
TX
AME
P
24
21
31
30
29
23
12
22
32
39
33
40
41
42
IN
5
8
7
#
T
YPE
O
O
O
O
O
O
I
I
I
I
I
I
I
Address Enable input (active low)
When AEN# transition to logic 0, it decodes and validates COM 1-4 ports
address per S1, S2 and S3 inputs.
Select 1 to 3
These are the standard PC COM 1-4 ports and IRQ selection inputs. See
Table 1
resistor.
Interrupt Request A, B and C Outputs (active high, tri-state)
These are the interrupt outputs associated with COM 1-4 to be connected to
the host data bus. See interrupt section for details. The Interrupt Requests A,
B or C functions as IRQx to the PC bus. IRQx is enabled by setting MCR bit-3
to logic 1 and the desired interrupt(s) in the interrupt enable register (IER).
Line Printer Port-1 Decode Logic Output (active low)
This pin functions as the PC standard LPT-1 printer port address decode logic
output, see
internally connected to the RCLK input in the PC mode.
Line Printer Port-2 Decode Logic Output (active low)
This pin functions as the PC standard LPT-2 printer port address decode logic
output, see
Transmit Data or wireless infrared transmit data
This output is active low in normal standard serial interface operation (RS-
232, RS-422 or RS-485) and active high in the infrared mode. Infrared mode
can be enabled by connecting pin ENIR to VCC or through software setting
after power up.
Receive Data or wireless infrared receive data
Normal received data input idles at logic 1 condition and logic 0 in the infrared
mode. The wireless infrared pulses are applied to the decoder. This input
must be connected to its idle logic state in either normal, logic 1, or infrared
mode, logic 0, else the receiver may report “receive break” and/or “error” con-
dition(s).
Request to Send or general purpose output (active low)
This port may be used for one of two functions:
1) automatic hardware flow control, see EFR bit-6, MCR bit-1and IER bit-6.
2) RS485 half-duplex direction control, see XFR bits 2 and 5.
RTS# output must be asserted before auto RTS flow control can start.
Clear to Send or general purpose input (active low)
If used for automatic hardware flow control, data transmission will be stopped
when this pin is de-asserted and will resume when this pin is asserted again.
See EFR bit-7 and IER bit-7.
Data Terminal Ready or general purpose output (active low)
Data Set Ready input or general purpose input (active low)
Carrier Detect input or general purpose input (active low)
Ring Indicator input or general purpose input (active low)
and
Table 1
Table 1
Table 3
5
. The baud rate generator clock output, BAUDOUT#, is
.
for details. The S1 pin has an internal 100k pull-up
2.25V TO 5.5V UART WITH 32-BYTE FIFO
D
ESCRIPTION
XR16L651