XR68C681 Datasheet, PDF (59/75 Pages) Exar Corporation – CMOS Dual Channel UART (DUART)

% ('
5
XR68C681
5

5
5


 ('%
5
Figure 27. An Illustration Depicting the Concept of Multi-Drop Mode
:*
* .
< *(
'
$$%%. *(
Figure 28. Bit Format of Character Data Being Transmitted in
the Multi-Drop Mode
  H% ( I ' ('%    H
( %I &  %(( -  ' ' &('&  & (
 H $$%%.I ( +-  $$     $ +  
' '  (% &('& %% ( (  (% + $ ( -
 %($ + & ' ' &" % % $ (
Figure 28
A    H% ( I  %   %(  '3 +
$    + % %%" ( +(% % $%   $$%%
&   ($ (+(%   H- I $$%% &
$(++% +  $ & (     (  ( (%  HI ( 
$$%% &  $  HI (  $ &
$$%% &" " ( %  H%I %  
' ' !(    '($ &  % (+ (  
( $(($ % $(' (% ( - $$%%$   '(
+   $$%%$ % (   $  $ (  +
'( +   $ &%   +%   %%  
  $$%%$ ( %  ( '(% $(%$"
 $ ( ' (   (-    $ &%   +%
 & (  ( $ -(     ! $$%% &
(%  %($ &   H% ('I
H.2.2 DUART Multi-Drop Operation
-( '   ( (     (% -$ ( 
  ($ $ & %( -  M=41N J H" I #  (%
$"   %($ ' ' ' %(%% +    ("
  -$  + $ (%"   $$%%.
 . +- (K  $   -$ , (  -  .
J  ( $('%     ' ' (% $"  ( . J 
($ (+(% ( %  $$%%
Transmitter Operation During Multi-Drop Mode
  %.
, ' %   % +    %($
' ' & -( -  MN +   '   (
 $( -   $ (% (    9 ( -  MN J
HI %% ( . J HI  $ %( -  MN J HI %% (
. J HI Figure 29 % %  '$ + $(-
+  %(( - ' '%  $$%%  "  ( (  
($ $
 
6