XR16C850CJ EXAR [Exar Corporation], XR16C850CJ Datasheet - Page 11

• Manufacturer Part Number: XR16C850CJ
• Manufacturer: EXAR [Exar Corporation]

SYMBOL DESCRIPTION
-DSR
-DTR
-RI
-RTS
RX / IRRX
Symbol
Rev. 1.20
40
37
33
39
32
10
44
41
37
43
36
11
Pin
48
39
33
32
41
7
52
42
36
44
35
7
Signal
type
O
O
I
I
I
11
reading MSR bit-4. This pin only affects the transmit
and receive operations when Auto CTS function is
enabled via the Enhanced Feature Register (EFR)
bit-7, for hardware flow control operation.
Data Set Ready (active low) - A logic 0 on this pin
indicates the modem or data set is powered-on and
is ready for data exchange with the UART. This pin
has no effect on the UART’s transmit or receive
operation.
Data Terminal Ready (active low) - A logic 0 on this
pin indicates that the 850 is powered-on and ready.
This pin can be controlled via the modem control
register. Writing a logic 1 to MCR bit-0 will set the -
DTR output to logic 0, enabling the modem. This pin
will be a logic 1 after writing a logic 0 to MCR bit-0,
or after a reset. This pin has no effect on the UART’s
transmit or receive operation.
Ring Indicator (active low) - A logic 0 on this pin
indicates the modem has received a ringing signal
from the telephone line. A logic 1 transition on this
input pin will generate an interrupt.
Request to Send (active low) - A logic 0 on the -RTS
pin indicates the transmitter has data ready and
waiting to send. Writing a logic 1 in the modem
control register (MCR bit-1) will set this pin to a logic
0 indicating data is available. After a reset this pin
will be set to a logic 1. This pin only affects the
transmit and receive operations when Auto RTS
function is enabled via the Enhanced Feature Reg-
ister (EFR) bit-6, for hardware flow control operation.
Receive Data - This pin provides the serial receive
data input to the 850. Two user selectable interface
options are available. The first option supports the
standard serial interface. The second option pro-
vides an Infrared decoder interface, see figures 2 and
3. When using the standard modem interface, the
RX input must be a logic 1 during idle (no data
Pin Description
XR16C850