XR16M2751_07 Datasheet, PDF (6/53 Pages) Exar Corporation – 1.62V TO 3.63V HIGH PERFORMANCE DUART WITH 64-BYTE FIFO

XR16M2751
1.62V TO 3.63V HIGH PERFORMANCE DUART WITH 64-BYTE FIFO
Pin Description
REV. 1.0.0
NAME
48-TQFP
PIN #
TYPE
DESCRIPTION
16/68#
24
I Intel or Motorola Bus Select.
When 16/68# pin is HIGH, 16 or Intel Mode, the device will operate in the Intel bus
type of interface.
When 16/68# pin is LOW, 68 or Motorola mode, the device will operate in the Motor-
ola bus type of interface.
CLKSEL
25
I Baud-Rate-Generator Input Clock Prescaler Select for channel A and B. This input is
only sampled during power up or a reset. Connect to VCC for divide by 1 and GND
for divide by 4. MCR[7] can override the state of this pin following a reset or initializa-
tion. See MCR bit-7 and Figure 5 in the Baud Rate Generator section.
HDCNTL#
37
I Auto RS-485 half-duplex direction output enable for channel A and B (active low).
Connect this pin to VCC for normal RTS# A/B function and to GND for auto RS-485
half-duplex direction output via the RTS# A/B pins. RTS# output goes low for transmit
and high for receive (polarity inversion is available via EMSR[3]). FCTR[3] in channel
A and B have control only if this input is disabled or at VCC.
RESET
36
(RESET#)
VCC
42
GND
17
I When 16/68# pin is HIGH for Intel bus interface, this input becomes RESET (active
high). When 16/68# pin is LOW for Motorola bus interface, this input becomes
RESET# (active low).
A 40 ns minimum active pulse on this pin will reset the internal registers and all out-
puts of channel A and B. The UART transmitter output will be held HIGH, the receiver
input will be ignored and outputs are reset during reset period (see Table 17).
Pwr _{1.62V to 3.63V power supply.}
Pwr _{Power supply common, ground.}
Pin type: I=Input, O=Output, I/O= Input/output, OD=Output Open Drain.
6