XR19L212 Datasheet, PDF (4/52 Pages) Exar Corporation – TWO CHANNEL INTEGRATED UART AND RS-232 TRANSCEIVER

XR19L212
TWO CHANNEL INTEGRATED UART AND RS-232 TRANSCEIVER
Pin Descriptions
REV. 1.0.0
NAME
48-QFN
PIN#
TYPE
DESCRIPTION
MODEM OR SERIAL I/O INTERFACE (EIA-232/RS-232 Voltage Levels)
TXDA
33
O _{UART Channel A Transmit Data. The TX signal will be LOW (< 1.5V) during reset or idle (no}
data).
RXDA
27
I _{UART Channel A Receive Data. The RX data input must idle LOW (< 1.5V). This input has}
an internal pull-down resistor and can be left unconnected when not used.
RTSA
24
O _{UART Channel A Request-to-Send or general purpose outputs. These outputs must be}
asserted prior to using auto RTS flow control, see EFR[6], MCR[1] and IER[6].
CTSA
48
I _{UART Channel A Clear-to-Send or general purpose inputs. It can be used for auto CTS}
flow control, see EFR[7], MSR[4] and IER[7]. This input has an internal pull-down resistor
and can be left unconnected when not used.
TXDB
22
O _{UART Channel B Transmit Data. The TX signal will be LOW (< 1.5V) during reset or idle (no}
data).
RXDB
25
I _{UART Channel B Receive Data. RXDB will be the input signal to the internal UART when}
RXBSEL is LOW. If RXB is used, then RXBSEL should be HIGH. The RX data input must
idle LOW (< 1.5V). This input has an internal pull-down resistor and can be left uncon-
nected when not used.
RTSB
3
O _{UART Channel B Request-to-Send or general purpose outputs. These outputs must be}
asserted prior to using auto RTS flow control, see EFR[6], MCR[1] and IER[6].
CTSB
2
I _{UARTChannel B Clear-to-Send or general purpose inputs. It can be used for auto CTS}
flow control, see EFR[7], MSR[4] and IER[7]. This input has an internal pull-down resistor
and can be left unconnected when not used.
SERIAL I/O INTERFACE (CMOS/TTL Voltage Levels)
TXB
9
O _{UART Channel B Transmit data. This is the TXB output signal from the UART. This pin can}
be used to communicate with an external Infrared or RS-422 transceiver if TXDB is unused.
RXB
8
I _{UART Channel B Receive data. This is the RXB input signal to the UART. If RXDB is not}
used (RXBSEL is HIGH), then this pin can be used to communicate with an external Infra-
red or RS-422 transceiver. If RXDB is used (RXBSEL is LOW), this pin should be left open.
ANCILLARY SIGNALS (CMOS/TTL Voltage Levels)
XTAL1
13
I _{Crystal or external clock input. This input is not 5V tolerant.}
XTAL2
14
O _{Crystal or buffered clock output. This output may be use to drive a clock buffer which can}
drive other device(s).
PwrSave 12
I _{Power-Save (active high). This feature isolates the L212’s data bus interface from the host}
preventing other bus activities that cause higher power drain during sleep mode. See Sleep
Mode with Auto Wake-up and Power-Save Feature section for details.
ACP
20
I _{Autosleep for Charge Pump (active HIGH). When this pin is HIGH, the charge pump is shut}
off if the L212 is already in partial sleep mode, i.e. the crystal oscillator is stopped. See
”Section 2.18, Sleep Modes and Power-Save Feature with Wake-Up Inter-
rupt” on page 19.
4