ML145428
LANSDALE Semiconductor, Inc.
ML145428 DSI
PIN
DESCRIPTIONS – cont’d
BC, BAUD CLOCK INPUT
This pin serves as an input for an externally supplied 16
times data clock. Otherwise, the BC pin expects a 4.096 MHz
clock signal which is internally divided to obtain the 16 times
clock for the most frequentlly used standard bit rates (see BR1
- BR3 pin description).
BRCLD, 16 TIMES CLOCK INTERNAL OUTPUT
This pin outputs the internal 16 times asynchronous data rate
clock.
BR1, BR2, BR3, BIT RATE SELECT INPUTS
These three pins select the asynchronous bit rate, either
externally supplied at the BC pin (16 times clock) or one of
the internally supplied bit rates. (See Table 1.)
DCO, DATA CHANNEL OUTPUT
This pin is a three–state output pin. Synchronous data is out-
put when DOE is high. This pin will go high impedance when
DOE or RESET are low. When CM is low, synchronous data is
output on DCO on the falling edges of DC as long as DOE is
high. When CM is high, synchronous data is output on DCO on
the rising edges of DC, while DOE is held high. No more than
eight data bits can be output during a given DOE high interval
when CM = high. This feature allows the DSI to interface direct-
ly with the MC145422/26 Universal Digital Loop Transceivers
(UDLT’s) and PABX time division multiplexed highways.
DOE, DATA OUTPUT
ENABLE
INPUT
See DCO pin description and the SYNCHRONOUS CHAN-
NEL INTERFACE section.
DIE, DATA INPUT
ENABLE
OUTPUT
See DCI and DCO pin descriptions and the SYNCHRO-
NOUS CHANNEL INTERFACE section.
CM, CLOCK MODE INPUT
See the SYNCHRONOUS CHANNEL INTERFACE section
and the SYNCHRONOUS CLOCKING MODE SUMMARY.
(See Table 2.)
RESET, RESET INPUT
When held low, this pin clears the internal FIFO’s, forces the
TxD asynchronous input to appear high to the DSI’s internal
circuitry, forces TxS and RxS low. When returned high, normal
operation results.
When the RESET input is returned high the DSI’s SYN-
CHRONOUS CHANNEL RECEIVER will not accept or trans-
fer any incoming data words on the DCI pin to the Rx FIFO
until one “flag” word is input at the DCI pin. (Also see RxS
pin description)
DCI, DATA CHANNEL INPUT
Synchronous data is input on this pin on the falling edges of
DC when DIE is high.
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