Author Topic: What does CAN ErrorPassive mean  (Read 6464 times)

Offline Jakob

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What does CAN ErrorPassive mean
« on: March 10, 2014, 02:40:47 PM »
Hello

I got a question from a customer, and at first I thought this was an easy question.

What does the CAN.ErrorPassive signal mean ?

I know its a new signal in the MCxx1xx series,
so I looked in the API specification, but all I found was this:
BIOS-name: ErrorPassive
Variable type: BOOL
Signal direction: Read
Function, Scaling: True = The Can controller is in error passive state.
 ???

Anybody out there know what it actually means?

Regards
 Jakob
« Last Edit: March 10, 2014, 03:52:01 PM by Jakob »

Offline Jakob

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Re: What does CAN ErrorPassive mean
« Reply #1 on: March 10, 2014, 04:12:31 PM »
A google search came up with this result, which I assume is valid for the plus1 CAN errorpassive state.

Copy pasted from "http://www.can-wiki.info/"

Error passive A node goes into error passive state if at least one of its error counters is greater than 127. It still takes part in bus activities, but it sends a passive error frame only, on errors. Furthermore, an error passive node has to wait an additional time (Suspend Transmission Field, 8 recessive bits after Intermission Field) after transmission of a message, before it can initiate a new data transfer. The primary passive error flag consists of 6 passive bits and thus is “transparent” on the bus and will not “jam” communications.


Offline pinias

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Re: What does CAN ErrorPassive mean
« Reply #2 on: March 13, 2014, 04:47:28 PM »
OK,

this may help:

if you run the CANKING and you get an error passive it means some device is at different baud rate (even the CAN KING).

Antonio


Offline Jakob

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Re: What does CAN ErrorPassive mean
« Reply #3 on: March 14, 2014, 03:26:47 PM »
Thank you Antonio,
Very good to know, I will check if this is the case here.

Jakob