NAME

Device::Chip::PCF8563 - chip driver for a PCF8563

SYNOPSIS

   use Device::Chip::PCF8563;
   use Future::AsyncAwait;

   use POSIX qw( mktime strftime );

   my $chip = Device::Chip::PCF8563->new;
   await $chip->mount( Device::Chip::Adapter::...->new );

   printf "The current time on this chip is ",
      await strftime( "%Y-%m-%d %H:%M:%S", localtime mktime $chip->read_time );

DESCRIPTION

This Device::Chip subclass provides specific communication to a NXP PCF8563 chip attached to a computer via an I²C adapter.

METHODS

The following methods documented in an await expression return Future instances.

read_time

   @tm = await $chip->read_time;

Returns a 7-element struct tm-compatible list of values by reading the timekeeping registers, suitable for passing to POSIX::mktime, etc... Note that the returned list does not contain the yday or is_dst fields.

Because the PCF8563 only stores a 2-digit year number plus a single century bit, the year is presumed to be in the range 2000-2199.

This method presumes POSIX-compatible semantics for the wday field stored on the chip; i.e. that 0 is Sunday.

This method performs an atomic reading of all the timekeeping registers as a single I²C transaction, so is preferrable to invoking multiple calls to individual read methods.

write_time

   await $chip->write_time( @tm );

Writes the timekeeping registers from a 7-element struct tm-compatible list of values. This method ignores the yday and is_dst fields, if present.

Because the PCF8563 only stores a 2-digit year number and a century bit, the year must be in the range 2000-2199 (i.e. numerical values of 100 to 299).

This method performs an atomic writing of all the timekeeping registers as a single I²C transaction, so is preferrable to invoking multiple calls to individual write methods.

AUTHOR

Paul Evans <leonerd@leonerd.org.uk>