Will Superposition of error flags desynchronize a active-transmitter passive-receiver bus??
"Christiano SA" <[email protected]> Mon, 20 Aug 2018 21:02:19 +0200
| Newsgroups | gmane.comp.hardware.bus.can |
|---|---|
| Message-ID | <trinity-00b6c04b-af1a-4f13-b9cd-ed4ae2451d1c-1534791739163@3c-app-mailcom-lxa03> |
Imagine the following situation: You have a bus with two nodes: node 1 = transmitter, active-error-node node 2 = receiver, passive-error-node Now an error happens at node 1. As it is a active node, it will transmit 6 dominant bits, but... lets suppose that the third bit generate an error in the node2. The ISO 11898-1:2015, in the page 35 says: """"""""""""""""""""""""""""""""""""""" Passive error flags initiated by receivers shall not be able to prevail over any activity on the bus. Therefore, error-passive receivers shall always wait for 6 subsequent equal bits after detecting an error condition. The passive error flag is complete when these 6 equals bits have been detected. """"""""""""""""""""""""""""""""""""""" So, from node2's view, it will have to wait 3 (6 total - past 3) dominant bits + 6 recessive bits to follow the rule "6 equal subsequent bits". At the end, node2 can enter in the "error delimiter". However, from the node1's view, it is remaining only 3 bits to enter in the "error delimiter". Isn't it happening desynchrony here? This question is being sended to 2 mailing lists: Canlist Opengarage group -- Archives and useful links: http://groups.yahoo.com/group/CANbus Subscribe and unsubscribe at www.vector.com/canlist/ Report any problems to <[email protected]>