XR68C681 Datasheet, PDF (6/75 Pages) Exar Corporation – CMOS Dual Channel UART (DUART)

XR68C681
PIN DESCRIPTION (CONT’D)
Pin Number
(44 pin PLCC)
Pin Number
(40 pin DIP)
11
1
1=
16
1
1/
1
1@
11
1<
1=
1
16
=
1/
=
1@
Symbol
Type Description
5
8

5
5.
:7
5
22


#,

.D25
5
*
#
7
 Transmitter Serial Data Output.
     % %(- (+
('  ( (%  %($ +(%  (%  (% $ (   3( -
 (-  %      %( (% ($" $(%$"  ( -
(   ' :,*
7 $ #+ !  ''3 (% %'(+($"
   %($ $ (% % (+$  +     %(  (+
-(%    +( - $- +   ''3
No Connect.
# Receiver Serial Data Input.
     % %(- (+(' 
( (% '($ +(% #+  !  '( ''3 (% %'(+($"
  '($ $ (% %$    (%( - $- +   ''3
#  
Crystal Output or External Clock Input.  (% ( (%   ' 
'( +   %($ +   '&%  $  ''(  - $
    (   %'( (% %$ #+   %'( (%  %$"
 !  ''3 %(-  %  %($   (% ( 
# $ +   5/<
/< $('  + '( &"   %
% %&  %(-  ( +C '(%   9G  $
= 9G  (% C(  '   & (   '&% %'(
  &   !  :'( ''3 %(- 
# Crystal Input.
 '( +   %($ +   '&% %(
+ 5.
:7 #+   %'( (% %$"  ''( % % 
' '$ +  (% (  - $  (% ( %  +  (+
 !  ''3 (% %($  5.
:7
# Master Reset.    (% ( '% (   -(%%  "
*" #" #" ," ,
" ( (((G%   #;   _/" %%
 
 .(" '%     ( %" ,  ,@ (
  -(' H (- I %"  $ '%  %( '  % (  
( '( % (   5  $ 5*  3( -  (- 
# Chip Select. '(    $ % (%  %$  

 (% (-   %+%   
,  $     ( 
 @   $  
 (% 
# Input 2. 0  % (   (% (  ' %  ' +(-
$  
. !  ''3 ( "    '   * '(

'3 #  5
*
# Interrupt Acknowledge. '( :  (% (  (%  
,.%
% %    (  C% (%%$ &     $('
A   
, %%%  (% ( " ( ( $('%      .%
(  C% (%    %('$"  $     & !
% '&' (   (  '3 $- '&'    
( % $   
,.% (  '3 $- & '( -  
'  % +   #  ;' -(% #;    $ %
  @
 
/