XR88C681 Datasheet, PDF (59/99 Pages) Exar Corporation – CMOS DUAL CHANNEL UART (DUART)

XR88C681
  %( - ' (E ((-%  & +   %(
$ ( % & ( -  $M%   '(
%( - ( "     ($(  +   ( ($%"  
' '  ' ' %(%  (% ' (% %''%%+
+  % %4
 # ++% ($(' ''(    '( %( -
( 
 # ((%   '( $(+     
%( - (  $M% %  &('&  %  (%
= ( ' ' A (&  $ , (%
 +" (+   % %'%  '( $   $ 
+ / $L  $'( +     ("  
'( ( -( %( -   $  / ! / J
61"/8I 8"  '   '( %
%$     > 61/38I ''3 %" ( (
3  (% '( %   ($(  +     ( 
 (% (   "   61/38I ''3 %(-  (% $(($$ & / 
-    % ''3 /8I +   ( ( -
$  $  $ (% +   ' '
  5==
/= $('% -(%   %   ( 
$'  !  (  ''3 %(-  % (   5 
/5 ''3 %(-  B     % (% -(  ' (' 
% (    5  /5 ''3 %(-    
'3 '
-(%%"   % (% $(%$  &% %   /5
''3" ( $  ((-   ++'% + '( $(+  
% (% +  $(%$   %   5 ''3 +%
+    "  %%   ( '( - %( $ % (%
%& '  % (   '( 5 ''3
D.6 Application Examples using the Timing Control
Block
# $  '(+&   % +   %%% ( (   (( -

  *'3"   !%  ( '$$
Example A: Using the BRG
%     % (% %  '(  $  %( $
   + 63% (
     % % $
  +( -4
 %  1/=/< 8I '&% %'( '%%  
5.
9:  $ 5 ( %L  $(( -  1/=/< 8I 9
%(-  (    5.
9: ( (   5 ( +( -
 B(  _/ 
 $ -(%   (% % ( %
   %( *0 ' 2! $ ( 5 J 
1 B( =_/ 
 $ -(%   (% % ( %
  '( *0 ' 2! $ ( 5 J 
< B( !!!!!!! 
  (% % %'% C*( D
 S  Table 18 +  (% $ % 
B     %++(! $ %  ( & !%%( "  $ !
$ %  C$ H 'D  +   ( & !%%( 
6 B( ==_/ 
   (% % %%   '(  $
 %( (  +
   63% 
Table 17  $ Table 18
Example B: Programming the Bit Rate via the
Counter/Timer
%   % (% %   %(  $ '( $ 
/63% (
  * Please note that this particular
bit rate is not offered by the BRG #  (% '%   % '
$   +( -
 (  < 8I 9 %(-  (    5.
9: ( "  (
  5 ( (% + +( -
 B( _/ 
  $ _/ 
9  (% %%
%% (  
. - ( -  %E  +
+E '& J < 8I.^NO J  8I
1 B(  
N/4<O  (% ( %  
. (   
( $"  $ %'   (( - %' +  
.
    5.
9: ( 
< B( _/ 
*  (% ( %'(+&     (( -
%' +   '(  $  %( +
  *
(  $($ +  
. Please note that when the
DUART is programmed in this configuration, the C/T
output represents a 16X over sample of the
Transmitted and Received data  +"   ' (
'('(& ( $(($    8I %E  & /" M%
(3 + ''3 %(- % (-( ( - +   *0
 %4 *(  J  8I./ J /63%
Example C: Using the External Input Ports
%  " ( $$((   ( -
  * 
/63% % 2! *" .%   %   %(  $
'( $   % (
  
  % $%  +  +   %% % $ (
2! *"  - (   +( -4
 B( !!!!!!    ,
  ,

 +(-( -(%
 (% % %    8I %E  +  
. 
   ,1
74 ! J $ H '
   %++(! $ %  ( & !%%(
 
6