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lib/Device/Chip/MAX7219.pm  view on Meta::CPAN

   await $chip->limit( $columns );

Sets the scan limit register. C<$value> must be between 1 and 8, to set
between 1 and 8 digits. This should only be used to adjust for the number of
LED digits or columns units physically attached to the chip; not for normal
display blanking, as it affects the overall intensity.

I<Note> that this is not directly the value written to the C<LIMIT> register.

=cut

async method limit ( $columns )
{
   $columns >= 1 and $columns <= 8 or
      croak "->limit columns must be between 1 and 8";

   await $self->_writereg( REG_LIMIT, $columns - 1 );
}

=head2 shutdown

   await $chip->shutdown( $off );

Sets the shutdown register, entirely blanking the display and turning off all
output if set to a true value, or restoring the display to its previous
content if set false.

I<Note> that this is not directly the value written to the C<SHUTDOWN>
register.

=cut

async method shutdown ( $off )
{
   await $self->_writereg( REG_SHUTDOWN, !$off );
}

=head2 displaytest

   await $chip->displaytest( $on );

Sets the display test register, overriding the output control and turning on
every LED if set to a true value, or restoring normal operation if set to
false.

=cut

async method displaytest ( $on )
{
   await $self->_writereg( REG_DTEST, $on );
}

=head1 AUTHOR

Paul Evans <leonerd@leonerd.org.uk>

=cut

while( readline DATA ) {
   my ( $hex, $segments ) = split m/=/;
   my $bits = 0;
   substr( $segments, $_, 1 ) eq "." and $bits += 1 << $_ for 0 .. 6;
   $hex2bits{$hex} = $bits;
}

0x55AA;

__DATA__
0= ......
1=    .. 
2=. .. ..
3=.  ....
4=..  .. 
5=.. .. .
6=..... .
7=    ...
8=.......
9=.. ....
A=... ...
B=.....  
C= ...  .
D=. .... 
E=....  .
F=...   .
-=.      
 =