73K224L
V.22bis, V.22, V.21, Bell 212A, 103
Single-Chip Modem
DATA SHEET
DTE USER INTERFACE
NAME
TYPE DESCRIPTION
EXCLK
I
External Clock. This signal is used in synchronous transmission when the
external timing option has been selected. In the external timing mode the rising
edge of EXCLK is used to strobe synchronous transmit data available on the
TXD pin. Also used for serial control interface.
RXCLK
O/
Receive Clock. Tri stateable. The falling edge of this clock output is coincident
Tristate with the transitions in the serial received data output. The rising edge of RXCLK
can be used to latch QAM or DPSK valid output data. RXCLK will be active as
long as a carrier is present.
RXD
O/
Received Digital Data Output. Serial receive data is available on this pin. The
Weak data is always valid on the rising edge of RXCLK when in synchronous mode.
Pull-up RXD will output constant marks if no carrier is detected.
TXCLK
O/
Transmit Clock. Tri stateable. This signal is used in synchronous transmission to
Tristate latch serial input data on the TXD pin. Data must be provided so that valid data is
available on the rising edge of the TXCLK. The transmit clock is derived from
different sources depending upon the synchronization mode selection. In Internal
Mode the clock is generated internally. In External Mode TXCLK is phase locked
to the EXCLK pin. In Slave Mode TXCLK is phase locked to the RXCLK pin.
TXCLK is always active.
TXD
I
Transmit Digital Data Input. Serial data for transmission is input on this pin. In
synchronous modes, the data must be valid on the rising edge of the TXCLK
clock. In asynchronous modes (2400/1200/600 bit/s or 300 baud) no clocking is
necessary. DPSK data must be +1%, -2.5% or +2.3%, -2.5 % in extended
overspeed mode.
ANALOG INTERFACE AND OSCILLATOR
RXA
TXA
I
O
I
Received modulated analog signal input from the phone line.
Transmit analog output to the phone line.
XTL1
XTL2
These pins are for the internal crystal oscillator requiring a 11.0592 MHz parallel
mode crystal. Two capacitors from these pins to ground are also required for
proper crystal operation. Consult crystal manufacturer for proper values. XTL2
can also be driven from an external clock.
I/O
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© 2005, 2008 TERIDIAN Semiconductor Corporation
Rev 7.1
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