CAN Message greater than 8bytes

[Naveenk.wins]

Hi,

Assume if i want to send 12bytes of Data in CAN message. Because we know max is 8bytes/Frame.

How to do that.

Best Regards
S.Naveen Kumar

 

[srikanthsamaga]

Send in 2 frames

 

[Naveenk.wins]

Hi,

It's not as simple as that....There is some sort of rule...Some sort of synchronization...

 

[horace1]

send the data as 2 frames with IDs identifing which frame is bytes 0 to 7 and 8 to 11

 

[srikanthsamaga]

Hi,

It's not as simple as that....There is some sort of rule...Some sort of synchronization...

I know that
But its not that hard also.
I am not an expert in CAN, but I think you should start transmitting second frame as soon as the interframe space of the first frame is over, If there is another higher priority message waiting then you have a problem.
So one thing what you can do is set the highest priority for the message which has more than 8 bytes and implement Horace1's idea.

Other CAN experts in this forum, correct me if I am wrong.

 

[horace1]

the numerically lowest ID has the highest priority (0's in an ID have higher priority than 1's and are transmitted on the bus)
so long as the protocol knows which ID is associated with a particular messages it can sort it out.