XR16M2551 Datasheet, PDF (6/51 Pages) Exar Corporation – HIGH PERFORMANCE LOW VOLTAGE DUART WITH 16-BYTE FIFO AND POWERSAVE FEATURE

XR16M2551
HIGH PERFORMANCE LOW VOLTAGE DUART WITH 16-BYTE FIFO AND POWERSAVE FEATURE
Pin Description
REV. 1.0.2
NAME
32-QFN 48-TQFP
TYPE
PIN # PIN #
DESCRIPTION
16/68#
17
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
Motorola 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
initialization. See MCR bit-7 and Figure 5 in the Baud Rate Generator section.
RESET 24
(RESET#)
36
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 16).
VCC
26
42 Pwr _{1.62V to 3.63V power supply.}
GND
13
17 Pwr _{Power supply common, ground.}
GND
Center N/A Pwr _{The center pad on the backside of the 32-QFN package is metallic and should be}
Pad
connected to GND on the PCB. The thermal pad size on the PCB should be the
approximate size of this center pad and should be solder mask defined. The solder
mask opening should be at least 0.0025" inwards from the edge of the PCB ther-
mal pad.
NC
-
37
- _{No connection.}
Pin type: I=Input, O=Output, I/O= Input/output, OD=Output Open Drain.
6