NAME

Device::Chip::DS1307 - chip driver for a DS1307

DESCRIPTION

This Device::Chip subclass provides specific communication to a Maxim Integrated DS1307 chip attached to a computer via an I²C adapter.

METHODS

The following methods documented with a trailing call to ->get return Future instances.

read_FIELD

   $v = $ds->read_I<FIELD>->get

Reads a timekeeping field and returns a decimal integer. The following fields are recognised:

 seconds minutes hours wday mday month year

The hours field is always returned in 24-hour mode, even if the chip is in 12-hour ("AM/PM") mode.

write_FIELD

   $ds->write_I<FIELD>->get

Writes a timekeeping field as a decimal integer. The following fields are recognised:

 seconds minutes hours wday mday month year

The hours field is always written back in 24-hour mode.

read_time

   @tm = $ds->read_time->get

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 DS1307 only stores a 2-digit year number, the year is presumed to be in the range 2000-2099.

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

   $ds->write_time( @tm )->get

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 DS1307 only stores a 2-digit year number, the year must be in the range 2000-2099 (i.e. numerical values of 100 to 199).

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>