RE: CAN-H and Vbatt Short

Hello John

<SNIP>
> But if the messages are always in error all the time the node won't 
> go
> bus off because it doesn't know there isn't a receiver out there. It
> just knows the message it put on the transmit pin doesn't match what
> it read back and will transmit forever. This will appear like the 
> node
> never returns to Error Active.
<SNIP

I don't agree with you on this. The Tx node will indeed try forever to 
send its message if it does not get back a positive ACK from a receiver. 
In this case however it will not get the ACK error, but probably a bit 
error, because it reads back something different as what was supposed to 
be sent. It is possible that it thinks it has not the highest priority 
and in that case it probably also sees the errors as a receiver. It 
would be nice if the error counters could be read out in this situation.

I think the node came into the bus-off state, because he mentioned it 
did not come back after removing the shortcut. If it was just error 
passive it would have returned.

Anyway it should be clear that CAN HIGH SPEED WILL NOT WORK WITH CAN HI 
(OR CAN LO) SHORTENED TO 12 VOLTS.

Kees

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