CCS C Software and Maintenance Offers
FAQFAQ   FAQForum Help   FAQOfficial CCS Support   SearchSearch  RegisterRegister 

ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

CCS does not monitor this forum on a regular basis.

Please do not post bug reports on this forum. Send them to CCS Technical Support
Transmission errors of CAN

 
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion
View previous topic :: View next topic  
Author Message
minttujatapsa



Joined: 19 Oct 2004
Posts: 2

View user's profile Send private message

Transmission errors of CAN
PostPosted: Fri May 06, 2005 5:15 am     Reply with quote
Hi,

Does anyone know how PICs handle the situation in where those cannot transmit data successfully. If I understood right it just gives up, and doesn't try resend automatically. Am I right?

If it do so, is there any way to force it to try transmitting until it will success?

Best regards

tr
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

View user's profile Send private message

PostPosted: Fri May 06, 2005 5:07 pm     Reply with quote
There are a few places in Microchip CAN Controller data sheets
where they say that the chip will do automatic re-transmission
in case of an error.

Quote:

From the MCP2510 data sheet, page 16:
After transmission of a message has begun, if an error
occurs on the bus or if the message loses arbitration,
the message will be retransmitted regardless of
a request to abort.


Quote:

From the MCP2515 data sheet, page 15:
Normally, if a CAN message loses arbitration or is destroyed
by an error frame, the message is retransmitted.


I can't find any statements in the 18F458 data sheet or Reference
manual that state it as openly as above.
Quote:
From the 18F Reference manual, in section 22.5.2:
Note that the automatic retransmission of messages on the
bus line is handled by the FSM.


AN713 has more information:
Quote:
On page 4, in the Error Passive section, it says:
When an Error-Passive node transmits a Passive Error Flag
and detects a dominant bit, it must see the bus as being idle
for eight additional bit times after an intermission before
recognizing the bus as available. After this time, it will
attempt to retransmit.


Quote:
In AN713, in the Bus-Off section, on page 4:
There is a bus recovery sequence that is defined by the CAN
protocol that allows a node that is Bus-Off to recover, return
to Error-Active, and begin transmitting again if the fault
condition is removed.
Display posts from previous:   
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group