XR88C681CP Datasheet, PDF (17/99 Pages) Exar Corporation – CMOS DUAL CHANNEL UART (DUART)

XR88C681
Bit 7




Bit 6




Bit 5




Bit 4




Description
Set Standby Mode (Channel A). B   (% '
 $ (% ( 3$ (  
 
 $ -(%
"  (% $ + ' +    %(%"
'(%" ' .(  $ $$((  '('(% 
'     (   % $&   
$ Please note that this command effects the
operation of the entire chip 7 ( (% 
%$ &  $ %  & ( 3( -   C2

#;2 2D ' $
Reset IUS Latch (Channel B). B   (% ' $
(% ( 3$ (  
  *
 $ -(%"
 $     (% ( - ( ?$" ( '%%
  #  $(' # '   %
 (%" (  " ( '%   #2   --
C (- D
Set Active Mode (Channel A). B   (% '
 $ (% ( 3$ (  
 
 $ -(%
"     (% $ +    $& $
 $ %%  ( 
Set Z-Mode (Channel B). B   (% ' $ (%
( 3$ (  
  *
 $ -(%"  
  (% ' $(( $   (   ?$ 
 $($ $(%'%%( +    H% (  (
(   ?$" ,% % Section C.6.2 7 (
 +   = ( #, '3-$ $('%
Reserved.
Reserved.
Table 3. Miscellaneous Commands, Upper Nibble of all Command Registers,
Unless Otherwise Specified (Cont’d)
# $$((    ' $%  ('  (  -
  ' $ -(%%"     % ++%
C $$%%(--$D ' $%  % ' $% 
(%$ ( Table 1" C  , 7 20#2
2#70DL  $  +  ($ (+($ & ( -
C% $$D ( Table 1 '(+('&"  % ' $% 4
  
72.#2
 7
 ,
72.#2
 7
 2 , , *#
 7

92  , , *#
 7
2' +  % ' $%  ( 3$ & (  $( - 
(( - $   ( '% $( -   $$%%% %
%'(+($ ( Table 1
 2!4
   
72.#2
 7 (% ( 3$ &
  '$ + $( -   $$%% 2_/ Please
note that this “Read Operation” will not result in placing
the contents of a DUART register on the data bus.  
 &  ( -   (  " ( % %   (% '$
(%  
 .( ( ( (( ' ( -   $($
$(%'%%( (    ( +  
 .(" %
% Section D.2
  ! +  $$%%(--$ ' $% (%
  C2 , , *#D
 $  (%
' $ (% ( 3$ & +( -  ( + $ 
  $$%% 2_/ B    % ( 3%  (%
' $" .%  (% %( - '( (%  CD ( (  
,  , -(%    (%" ( (   ,
  %'(+($   %"   '  -$   % +  
  ( %  ' % +   ( $(($ (%
( (   , 8 '" (+ ,NO (% %  CD"   % +
  '% $( -   ( " ," (%  %  
-(' CD
 %E &"   '  ( 3 +   C2
, , *#D ' $ %   C
92 
, , ,#7D ' $    $($
$(%'%%( (    ( +    ,%" %
% Section F
 
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