File Coverage

blib/lib/Device/Chip/AD9833.pm

Criterion	Covered	Total	%
statement	70	89	78.6
branch	5	16	31.2
condition			n/a
subroutine	15	17	88.2
pod	7	8	87.5
total	97	130	74.6

#  You may distribute under the terms of either the GNU General Public License
#  or the Artistic License (the same terms as Perl itself)
#
#  (C) Paul Evans, 2020-2022 -- [e-mail]

use v5.26;
use Object::Pad 0.73 ':experimental(init_expr)';

package Device::Chip::AD9833 0.04;
class Device::Chip::AD9833
   :isa(Device::Chip);

use Carp;
use Data::Bitfield 0.02 qw( bitfield boolfield );

use Future::AsyncAwait 0.38; # aync method

use constant PROTOCOL => "SPI";

use constant {
   REG_CONFIG => 0x0000,
   REG_FREQ0  => 0x4000,
   REG_FREQ1  => 0x8000,
   REG_PHASE0 => 0xC000,
   REG_PHASE1 => 0xE000,
};

=head1 NAME

C - chip driver for F

=head1 SYNOPSIS

   use Device::Chip::AD9833;
   use Future::AsyncAwait;

   my $chip = Device::Chip::AD9833->new;
   await $chip->mount( Device::Chip::Adapter::...->new );

   await $chip->init;

   my $freq = 440; # in Hz
   await $chip->write_FREQ0( ( $freq << 28 ) / 25E6 ); # presuming 25MHz reference

=head1 DESCRIPTION

This L subclass provides specific communication to an
F F attached to a computer via an SPI adapter.

The reader is presumed to be familiar with the general operation of this chip;
the documentation here will not attempt to explain or define chip-specific
concepts or features, only the use of this module to access them.

=cut

sub SPI_options
{
   return ( mode => 2 );
}

field $_config = 0;

async method _write ( $word )
{
   await $self->protocol->write( pack "S>", $word )
}

=head1 METHODS

The following methods documented in an C expression return L
instances.

=cut

=head2 init

   await $chip->init;

Resets the chip to a working configuration, including setting the C bit
appropriately for the way this module writes the frequency registers.

This method must be called before setting the frequency using L
or L.

=cut

async method init ()
{
   await $self->_write( REG_CONFIG | 0x2100 ); # RESET, B28=1
   await $self->_write( REG_CONFIG | 0x2000 ); # unreset, B28=1
}

bitfield { format => "integer" }, CONFIG =>
   B28     => boolfield( 13 ),
   HLB     => boolfield( 12 ),
   FSELECT => boolfield( 11 ),
   PSELECT => boolfield( 10 ),
   SLEEP1  => boolfield(  7 ),
   SLEEP12 => boolfield(  6 ),
   OPBITEN => boolfield(  5 ),
   DIV2    => boolfield(  3 ),
   MODE    => boolfield(  1 );

=head2 read_config

   $config = await $chip->read_config;

Returns a C reference containing the current chip configuration. Note
that since the chip does not support querying the configuration, this is just
an in-memory copy maintained by the object instance, updated by calls to
L.

The hash will contain the following named fields, all booleans.

   B28
   HLB
   FSELECT
   PSELECT
   SLEEP1
   SLEEP12
   OPBITEN
   DIV2
   MODE

In addition, a new value C will be created combining the current
settings of C, C and C to explain the waveform generated

   wave => "sine" | "triangle" | "square" | "square/2"

=cut

async method read_config ()
{
   my %config = unpack_CONFIG( $_config );

   my $wave;
   if( $config{OPBITEN} ) {
      $wave = $config{DIV2} ? "square" : "square/2";
   }
   elsif( $config{MODE} ) {
      $wave = "triangle";
   }
   else {
      $wave = "sine";
   }
   $config{wave} = $wave;

   return \%config;
}

=head2 change_config

   await $chip->change_config( %changes );

Writes updates to the chip configuration. Takes named arguments of the same
form as returned by L, including the synthesized C
setting.

=cut

async method change_config ( %changes )
{
   if( defined( my $wave = delete $changes{wave} ) ) {{
      $changes{OPBITEN} = 1, $changes{MODE} = 0, $changes{DIV2} = 1, last if $wave eq "square";
      $changes{OPBITEN} = 1, $changes{MODE} = 0, $changes{DIV2} = 0, last if $wave eq "square/2";
      $changes{OPBITEN} = 0, $changes{MODE} = 1, last if $wave eq "triangle";
      $changes{OPBITEN} = 0, $changes{MODE} = 0, last if $wave eq "sine";
      croak "Unrecognised value for 'wave' configuration - $wave";
   }}

   my %config = ( unpack_CONFIG( $_config ), %changes );

   $config{B28} = 1;

   await $self->_write( REG_CONFIG | ( $_config = pack_CONFIG( %config ) ) );
}

=head2 write_FREQ0

=head2 write_FREQ1

   await $chip->write_FREQ0( $freq );
   await $chip->write_FREQ1( $freq );

Writes the C or C frequency control register. C<$freq> should
be a 28bit integer value.

=cut

async method write_FREQ0 ( $freq )
{
   await $self->_write( REG_FREQ0 | ( $freq & 0x3FFF ) );
   await $self->_write( REG_FREQ0 | ( $freq >> 14 ) );
}

async method write_FREQ1 ( $freq )
{
   await $self->_write( REG_FREQ1 | ( $freq & 0x3FFF ) );
   await $self->_write( REG_FREQ1 | ( $freq >> 14 ) );
}

=head2 write_PHASE0

=head2 write_PHASE1

   await $chip->write_PHASE0( $phase );
   await $chip->write_PHASE1( $phase );

Writes the C or C phase control register. C<$phase> should
be a 12bit integer value.

=cut

async method write_PHASE0 ( $phase )
{
   await $self->_write( REG_PHASE0 | $phase );
}

async method write_PHASE1 ( $phase )
{
   await $self->_write( REG_PHASE1 | $phase );
}

=head1 AUTHOR

Paul Evans

=cut

0x55AA;