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=head2 read_max_temperature

   $temperature = await $chip->read_min_temperature;

   $temperature = await $chip->read_max_temperature;

Returns the values of the C<T_MIN> and C<T_MAX> registers, suitably converted
into metres.

=head2 clear_min_temperature

=head2 clear_max_temperature

   await $chip->clear_min_temperature;

   await $chip->clear_max_temperature;

Clear the C<T_MIN> or C<T_MAX> registers, resetting them to start again from
the next measurement.

=cut

async method read_min_temperature () { return await $self->_mplread_t( REG_T_MIN_MSB ) }
async method read_max_temperature () { return await $self->_mplread_t( REG_T_MAX_MSB ) }

async method clear_min_temperature () { return await $self->write_reg( REG_T_MIN_MSB, "\x00\x00" ) }
async method clear_max_temperature () { return await $self->write_reg( REG_T_MAX_MSB, "\x00\x00" ) }

=head1 METHODS

=cut

=head2 check_id

   await $chip->check_id;

Reads the C<WHO_AM_I> register and checks for a valid ID result. The returned
future fails if the expected result is not received.

=cut

async method check_id ()
{
   my $val = await $self->read_reg( REG_WHO_AM_I, 1 );

   my $id = unpack "C", $val;
   $id == WHO_AM_I_ID or
      die sprintf "Incorrect response from WHO_AM_I register (got %02X, expected %02X)\n",
         $id, WHO_AM_I_ID;

   return $self;
}

=head2 start_oneshot

   await $chip->start_oneshot;

Sets the C<OST> bit of C<CTRL_REG1> to start a one-shot measurement when in
standby mode. After calling this method you will need to use
C<busywait_oneshot> to wait for the measurement to finish, or rely somehow on
the interrupts.

=cut

async method start_oneshot ()
{
   my $bytes = await $self->_cached_read_ctrlreg;

   my $ctrl_reg1 = substr( $bytes, 0, 1 ) | "\x02"; # Set OST bit
   await $self->write_reg( REG_CTRL_REG1, $ctrl_reg1 );
}

=head2 busywait_oneshot

   await $chip->busywait_oneshot;

Repeatedly reads the C<OST> bit of C<CTRL_REG1> until it becomes clear.

=cut

async method busywait_oneshot ()
{
   while(1) {
      my $ctrl_reg1 = await $self->read_reg( REG_CTRL_REG1, 1 );
      last if not( ord( $ctrl_reg1 ) & 0x02 );
   }
}

=head2 oneshot

   await $chip->oneshot;

A convenient wrapper around C<start_oneshot> and C<busywait_oneshot>.

=cut

async method oneshot ()
{
   await $self->start_oneshot;
   await $self->busywait_oneshot;
}

field $_pending_trigger;

method _next_trigger
{
   return $_pending_trigger //=
      $self->oneshot->on_ready(sub { undef $_pending_trigger; });
}

=head1 AUTHOR

Paul Evans <leonerd@leonerd.org.uk>

=cut

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