+
+## Time Triggerred CANopen PDO Messages
+
+The VCA code places infrastructure there, but not all features
+are finished. It is waiting to some spare time, project funding,
+students diploma thesis work or contributors.
+
+The PDO can be sent as response to the source value change notification
+over event connectors. This is tested, works and is probably most
+complicated mode if should be done without polling.
+The SYNC driven and time driven modes needs to be implemented.
+The function _pdo_hub_event() should be divided into part processed
+at variable change notification, which only marks fields requiring
+update and PDO should be moved on list of Tx PDOs which require
+more processing. The second part should do real update and sending.
+Then PDO processor should take PDO from the list, update it and send
+it to the CAN bus. SYNC response would mean only connecting
+of SYNC filer and new rx_hub on PDO processor through
+vcaNet_msg_rec_connect(). SYNC processing would mean only marking PDO
+as requiring to be sent. Each PDO should contain timer field and then
+periodic mode could be implemented as marking PDO to be sent
+in timer call-back.
+
+The function vcaPDOProcessor_processMsg() is alternative to use
+of the full vcaNet_msg_rec_connect() infrastructure.
+So yes, above mentioned functionality of marking
+SYNC triggered PDOs for Tx could be added there.
+The key is to refactor _pdo_hub_event() function and addition
+of list for PDOs with pending requests.