One discovered PDO supplied to EtherCAT.Driver.signal_model/2.
Direction is from the master's perspective. bit_offset is relative to its
SyncManager image; bit_size is the PDO's complete size in bits. A signal's
offset is relative to this PDO instead.
Summary
Types
@type t() :: %EtherCAT.Driver.PDO{ bit_offset: non_neg_integer(), bit_size: non_neg_integer(), direction: :input | :output, index: non_neg_integer(), sm_index: non_neg_integer() }