XR68C681 Datasheet, PDF (38/75 Pages) Exar Corporation – CMOS Dual Channel UART (DUART)

XR68C681
Bits 7 - 4: “Change in Logic State” Identification Bits
 % (+($%  H%  $I  $  ' $ & H
 - +  '%I  % H
 - + 
'%I  ($$ + (  ( % #,  - #,1 #+  % H
 - +  '%I $'  '  - ( -('
% (  & +  % + (  ( %"    & ( ($ (+&   H--( -I (  & %( -   '% $( - HI (+($
( (   #,
  HI #+   H
 - +  '%I $  $'  '  - + %"   (' ( "    &
( +'  (% & 3( -   '% $( - (+($% %  HI
#   $%" (+ (  ( #,1 !( '%  '  - ( -(' %"   ( @ ( ' (  -(' HI
Bits 3 - 0: “The Current State of Input Pins IP0 - IP3”
 % (+($% H$  &I  $ +'   '  -(' %    #,  - #,1 (  ( %
# $      H#  ,
 - + I ( "   % $   +( -
 A(   ( $     ( +
   ( +% +
 (% % $  ,% 
    (' (%" ( (  
 -(%"  % $$
    ( +   #,
 ( ( $('  (' +   + ( % ( % !( '$   '  - + %  
 ( +   #,
 % %   %  % +  % ( %  +"   $( -   #,
" ( 
% %    H
 - + I ( "  
, ( $( 4
   (  ( %   --$
   +(  % +   '  -( - (  (
 ( - # M@N
Bit 7
BRG Set
Select
 J  
 J  
Bit 6
Bit 5
Bit 4
Counter/Timer Mode and Source
 Table 7
Bit3
Delta IP3
Interrupt
J
 J 8
Bit 2
Delta IP2
Interrupt
J
 J 8
Bit 1
Delta IP1
Interrupt
J
 J 8
Bit 0
Delta IP0
Interrupt
J
 J 8
Table 14. ACR- Auxiliary Control Register
Note:
This “two-tiered” interrupt enabling/disabling approach, for the “Input Change of State” interrupt allows tremendous flexibility for the
user. Setting or clearing the bits in ACR[3:0] allows the user to specify exactly which Input Port pins to be enabled (or disabled) for
generating the “Input Port Change of State” interrupt. Setting or clearing IMR[7] allows the user to “globally” enable or disable this
interrupt.
 
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